Publications by authors named "Amitava Dasgupta"

133 Publications

Merits of Monitoring Free Carbamazepine Measurements with an Automated Method.

Authors:
Amitava Dasgupta

J Appl Lab Med 2020 03;5(2):251-253

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston, Houston, TX.

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http://dx.doi.org/10.1093/jalm/jfz023DOI Listing
March 2020

Analytical Performance Evaluation of Aptima Herpes Simplex Virus 1 and 2 Assay Using Hologic Panther Instrument.

Ann Clin Lab Sci 2020 Mar;50(2):278-281

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston, Houston, TX, USA

Objective: Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are responsible for a variety of human diseases. Therefore, rapid detection of these viruses in clinical laboratory is important. Recently Aptima Herpes Simplex 1 and 2 assay has been approved by the FDA. We evaluated analytical performance of this assay by comparing results obtained by analysis of cultures.

Materials And Methods: Aptima Herpes Simplex assay is a nucleic acid amplification test that can be fully automated using the Hologic Panther instrument. This is a qualitative test providing either positive or negative result. We analyzed 115 specimens collected from anogenital locations using the new Aptima Herpes Simplex assay and our current tissue culture method.

Results: We observed good correlation between results obtained by using Aptima assay and the tissue culture method in 101 specimens but 14 specimens showed discordant results. Further testing in a reference laboratory using PCR (polymerase chain reaction) showed results in agreement with the Aptima assay but not the tissue culture method. The cause of discordance was misidentification of HSV-2 as HSV-1 by the tissue culture method.

Conclusions: Aptima Herpes simplex assay on the Hologic Panther instrument is suitable for rapid detection of herpes simplex virus in clinical laboratory.
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March 2020

Distortions but not Definitive Peaks by Capillary Serum Protein Electrophoresis Indicate Monoclonal Gammopathy of Undetermined Significance rather than Multiple Myeloma.

Ann Clin Lab Sci 2020 Jan;50(1):151-152

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School, Houston, TX, USA

Objective: Capillary electrophoresis of serum proteins demonstrates occasional distortions. Distortions or peaks in the gamma, beta, and alpha-2 zones may represent monoclonal gammopathy. In this study, we investigated if such distortions are associated with monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma.

Methods: Consecutive serum protein electrophoresis results were reviewed and immunofixation studies were recommended on specimens exhibiting distortions or distinct peaks in the gamma, beta or alpha-2 zones.

Results And Discussion: Of the 471 cases, we observed distortions in 101 cases. In the immunofixation studies, 17.8% of cases had a diagnosis of MGUS, but none contained multiple myeloma.

Conclusions: We conclude that distortions in serum capillary electrophoresis may be associated with MGUS, but not multiple myeloma.
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January 2020

Clinicopathological complexity in the application of the universal definition of myocardial infarction.

Cardiovasc Pathol 2020 Jan - Feb;44:107153. Epub 2019 Oct 10.

Department of Pathology, The Ohio State University (OSU), United States.

A universal definition of myocardial infarction (UDMI) has been established, periodically updated, and refined over the past twenty years. The primary purpose of the UDMI is to bring uniformity and accuracy to clinical diagnosis. Herein, a review and analysis of the UDMI is presented with emphasis on clinicopathological correlation. Determination of the presence of myocardial injury is based on the detection of abnormal serum cardiac biomarkers, particularly cardiac troponin (cTn), and in the current fourth iteration of the UDMI, high sensitivity (hs)-cTn. Differentiation of myocardial infarction from other causes of myocardial injury requires the documentation of clinical evidence of myocardial ischemia. In this review, difficulties in applying the UDMI in actual practice are discussed, based on the experience and perspective of those of us who face these problems as part of our own practice of pathology. The complexity in application of the UDMI is highlighted by the presentation of five illustrative cases involving the differential diagnosis of myocardial injury and myocardial infarction due to atherothrombotic and nonatherothrombotic coronary artery disease. The cases include myocardial infarction due to severe coronary atherosclerosis, supply-demand mismatch, coronary artery dissection associated with an eosinophilic coronary periarteritis, and coronary thromboembolism, and a case with a differential diagnosis of myocarditis and myocardial infarction. These cases illustrate how pathological findings can contribute to more accurate application of the UDMI and how, when critically applied, the UDMI can be used to better characterize myocardial infarcts in clinical practice.
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http://dx.doi.org/10.1016/j.carpath.2019.107153DOI Listing
March 2020

Contamination of Some Kratom Products with .

Ann Clin Lab Sci 2019 Sep;49(5):675-677

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston, Houston, TX, USA

Objective: Recently, the US Food and Drug Administration investigated the contamination of kratom (Mitragyna speciosa) by , an event that caused an outbreak in 20 states after its consumption. Therefore, we investigated 16 different bags of kratom submitted for testing for potential contamination with and other microorganisms within the Public Health Laboratory for the state of South Carolina.

Materials And Methods: All kratom powders collected were analyzed for potential contamination with bacteria by an in-house modified Food and Drug Administration's Bacteriological Analytical Manual procedure.

Results: Out of 16 products analyzed, six brands have unknown manufacturers, but manufacturer information was available for the other 10 products. In total, three brands of kratom showed presence of any .

Conclusions: Recently analyzed kratom products show a presence of .
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September 2019

Overutilization of Test for Hemoglobinopathy Evaluation: Experience from a Tertiary Care Academic Medical Center.

Ann Clin Lab Sci 2019 May;49(3):400-402

Department of Pathology and Laboratory Medicine The University of Texas Health Science Center McGovern Medical School, Houston, TX, USA

Background: Hemoglobin electrophoresis is a common clinical laboratory test for the identification of hemoglobinopathies in clinical practice. We investigated the utilization of this test in our academic teaching hospital and hypothesized that hemoglobin electrophoresis evaluation is overutilized at this institution.

Methods: 128 consecutive cases were analyzed and their medical records were studied to determine the clinical indication for the hemoglobin electrophoresis.

Results: Of the 128 cases studied, only 44% of cases had a justifiable reason for obtaining the hemoglobin electrophoresis, whereas the remaining 56% of cases did not have an acceptable indication for obtaining the test.

Conclusions: We conclude that hemoglobin electrophoresis is overutilized in our academic medical center and we recommend consultation with clinical pathologists prior to ordering such tests.
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May 2019

: Analytical Performance Evaluation of Electrochemiluminescence Cyclosporine Assay on Cobas e411 Analyzer.

Ann Clin Lab Sci 2019 Mar;49(2):271-273

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston and Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, TX, USA.

Background: Roche Diagnostics has developed electrochemiluminescence cyclosporine assay for application on multiple platforms including Cobas e 411 analyzer. This assay is not yet approved by the FDA for clinical application. We evaluated analytic performance of this new assay.

Methods: Within run, between run and linearity of this new assay were evaluated. In addition, cyclosporine values in 100 specimens obtained by using this new method were compared with values obtained by using the CMIA assay (Abbott Laboratories).

Results: New electrochemiluminescence cyclosporine assay showed excellent precision and accuracy. Comparing cyclosporine values obtained by using the CMIA tacrolimus assay (x-axis) with corresponding values obtained by using the Cobas tacrolimus assay (y-axis), the following regression equation was observed: y=0.9446x-2.018 (n=100, r=0.99).

Conclusion: The new electrochemiluminescence cyclosporine assay is comparable to the FDA approved CMIA tacrolimus assay. Therefore, when this assay is approved by the FDA, it can be used for therapeutic drug monitoring of cyclosporine.
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March 2019

Taking Advantage of Assay Harmonization, Biotin Interference in the LOCI Digoxin Assay Could Be Eliminated by Using the ADVIA Centaur Digoxin Assay.

Ann Clin Lab Sci 2018 Sep;48(5):614-617

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston and Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, Texas, USA.

Biotin at elevated concentration interferes with immunoassays that utilize biotin in assay design. We earlier reported interference of biotin in the luminescent oxygen channeling assay (LOCI) digoxin assay which utilizes biotinylated antibody against digoxin. However, the ADVIA Centaur digoxin assay, also manufactured by Siemens Diagnostics, does not utilize biotin in assay design. We hypothesized that if the LOCI and the ADVIA Centaur digoxin assay are harmonized, then interference of biotin in the LOCI digoxin assay could be eliminated by using the ADVIA Centaur digoxin assay. We analyzed 25 specimens from patients receiving digoxin using both assays to investigate harmonization between these two assays. Then aliquots of drug-free serum pool were supplemented with various biotin concentrations (range: 10 ng/mL to 2000 ng/mL) followed by measuring apparent digoxin levels using the ADVIA Centaur digoxin assay. In another set of experiments, aliquots of a serum digoxin pool were supplemented with biotin (10-2000 ng/mL) and digoxin concentrations were measured by the ADVIA Centaur digoxin assay. We observed an excellent correlation between digoxin values obtained by the LOCI digoxin assay (reference method) and the ADVIA Centaur digoxin assay (y= 1.0514 x+0.1083, r=0.99) indicating that both assays are harmonized. We did not observe any interference of biotin even at a highly elevated concentration of 2000 ng/mL with the ADVIA Centaur digoxin assay. We conclude that taking advantage of assay harmonization, interference of biotin in the LOCI digoxin assay can be eliminated by using the ADVIA Centaur digoxin assay.
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September 2018

Biotin interference in TSH, FT4, and FT3 assays based on the LOCI technology: Identifying interference by dilution.

J Clin Lab Anal 2019 Feb 17;33(2):e22667. Epub 2018 Sep 17.

Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, Texas.

Background: Although biotin interferences in TSH, FT3, FT4, and other biotinylated antibody-based assays manufactured by Roche Diagnostics have been well studied, there are relatively few reports on biotin interference in biotin-based assays manufactured by other companies. We investigated biotin interferences in TSH, FT4, and FT3 assays based on the LOCI (luminescent oxygen channeling assay) technology using the Dimension Vista 1500 analyzer (Siemens).

Methods: We prepared four serum pools using leftover specimens. Three serum pools were prepared initially for the original study but the 4 pool was prepared three months later. The aliquots of serum pool one and two were supplemented with various amounts of biotin (50 -1200 ng/mL) followed by determination of TSH, FT4, and FT3 concentrations. The aliquots of third pool were also supplemented with biotin to investigate whether 1:3 dilution could identify biotin interference. Aliquots of serum pool four were supplemented with biotin in order to study reproducibility of our original data.

Results: We observed significantly elevated FT3 levels at biotin concentration of 100 ng/mL. In contrast, FT4 levels were falsely elevated but TSH levels were falsely decreased at a biotin level of 500 ng/mL. We also observed nonlinearity in dilution experiment.

Conclusions: We conclude that FT3 assay is most susceptible to biotin interference (threshold: 100 ng/mL) while the FT4 and TSH assays are less affected (threshold: 500 ng/mL). In addition, we also observed nonlinearity upon 1:3 dilution, which may indicate biotin interference (or interference from other compounds).
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http://dx.doi.org/10.1002/jcla.22667DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6818550PMC
February 2019

Convallatoxin, the active cardiac glycoside of lily of the valley, minimally affects the ADVIA Centaur digoxin assay.

J Clin Lab Anal 2018 Oct 31;32(8):e22583. Epub 2018 May 31.

Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, TX, USA.

Objective: Lily of the valley is a poisonous plant due to the presence of the cardiac glycoside convallatoxin which is known to interfere with serum digoxin measurement using the LOCI digoxin assay and other digoxin assays. We evaluated potential interference of convallatoxin as well as extract of lily of the valley with the ADVIA Centaur digoxin assay by comparing results obtained using the LOCI digoxin assay.

Materials And Methods: Aliquots of a drug-free serum pool and a digoxin serum pool were supplemented with nanograms to 1 μg quantities of convallatoxin or 1.0 and 2.5 μL of lily of the valley extract per milliliter of serum followed by measurement of digoxin concentrations using the LOCI and ADVIA Centaur digoxin assays.

Results: Apparent digoxin concentrations were minimal using the ADVIA Centaur digoxin assay when aliquots of drug-free serum were supplemented with convallatoxin or extract of lily of the valley but apparent digoxin levels were very high using the LOCI digoxin assay. Moreover, minimal interference in serum digoxin measurement using the ADVIA Centaur digoxin assay was observed when aliquots of serum digoxin pool were further supplemented with lily of the valley extract. As expected, the LOCI digoxin assay showed significant interference of convallatoxin in serum digoxin measurement.

Conclusions: Significant interference of convallatoxin in serum digoxin measurement using the LOCI digoxin assay could be minimized using the ADVIA Centaur digoxin assay.
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http://dx.doi.org/10.1002/jcla.22583DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6817247PMC
October 2018

Biotin at High Concentration Interferes with the LOCI Digoxin Assay but the PETINIA Phenytoin Assay Is Not Affected.

Ann Clin Lab Sci 2018 Mar;48(2):164-167

Department of Pathology and Laboratory Medicine, University of Texas McGovern Medical School at Houston and Laboratory Services, Memorial-Hermann Hospital at Texas Medical Center, Houston, Texas, USA

Many automated immunoassays incorporate biotinylated antibodies and streptavidin-coated magnetic beads in the assay design. Biotin at elevated concentrations may interfere with these immunoassays. We evaluated potential interference of biotin on serum digoxin (LOCI assay utilizing biotinylated antibody) and phenytoin (PETINIA assay; no biotinylated antibody) measurements using the Vista 1500 analyzer. Aliquots of drug-free serum pool were supplemented with various biotin concentrations (range: 1 ng/mL to 250 ng/mL) followed by measuring apparent digoxin and phenytoin levels using appropriate immunoassays. In the second set of experiments, one serum pool was prepared from patients taking digoxin and another from patients taking phenytoin. Then aliquots of these serum pools were further supplemented with biotin followed by measuring digoxin or phenytoin concentrations. We observed apparent digoxin levels at 50 ng/mL biotin concentration or higher and also significant interference of biotin in serum digoxin measurement at a biotin concentration of 250 ng/mL. In contrast, we observed no interference of biotin in serum phenytoin measurement. We conclude that biotin interferes with the LOCI digoxin assay at a high concentration only.
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March 2018

Can Tranexamic Acid Reduce Blood Loss during Major Cardiac Surgery? A Pilot Study.

Ann Clin Lab Sci 2017 Sep;47(5):600-603

Department of Pathology and Laboratory Medicine, The University of Texas McGovern Medical School at Houston, Houston, TX, USA

We examined the effectiveness of tranexamic acid in preventing intraoperative blood loss during major cardiac surgery. Out of initial 81 patients undergoing major cardiac surgery (both coronary artery bypass and valve repair procedures) at our teaching hospital, sixty-seven patients were selected for this study. We compared estimated blood loss, decrease in percent hemoglobin and hematocrit following surgery between two groups of patients (none of them received any blood product during surgery), one group receiving no tranexamic acid (n=17) and another group receiving tranexamic acid (n=25). In the second study, we combined these patients with patients receiving modest amounts of blood products (1-2 unit) and compared these parameters between two groups of patients (25 patients received no tranexamic acid, 42 patients received tranexamic acid). In patients who received no blood product during surgery, those who received no tranexamic acid showed statistically significant (independent t-test two tailed at <0.05) reduced estimated blood loss (mean: 713.5 mL, SD: 351.6, n=17) compared to those who received tranexamic acid (mean: 987.2 mL, SD: 459.9, n=25). We observed similar results when the patients receiving no blood products and patients receiving modest amount of blood products were combined based on the use of tranexamic acid or not. No statistically significant difference was observed in percent reduced hemoglobin or hematocrit following surgery in any group of patients. We conclude that intraoperative antifibrinolytic therapy with tranexamic acid does not reduce intraoperative blood loss during major cardiac surgery which contradicts popular belief.
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September 2017

Model analysis of bidirectional interference in two-stage labeled-ligand immunoassays.

Clin Biochem 2017 Dec 10;50(18):1188-1197. Epub 2017 Aug 10.

Department of Pathology, Jefferson University Hospital, Philadelphia, PA, USA. Electronic address:

Objectives: Immunoassays involving sample incubation followed by a wash step prior to introduction of labeled analyte are potentially subject to both positive and negative interference (bidirectional interference) by a competing ligand. We examine this phenomenon from a theoretical standpoint using a mathematical model for sequential-step immunoassays in the presence of interferent.

Design & Methods: Competitive binding to antibody between analyte and interferent was modeled for sequential-step immunoassays. A primary assumption was that the ratio of affinity constants between the intended analyte and the interferent reflected the ratio of dissociation rate constants, with the higher dissociation rate constant for the lesser affinity ligand.

Results: Relationships of parameters (relative affinity constants, relative concentrations) for analyte and interferent were determined for conditions in which bidirectional interference can occur, for both steady-state and non-steady-state sample incubation conditions. Non-steady state sample incubation conditions can enhance the effects of an interferent. Homogeneous assay formats utilizing labeled ligand without a wash step can also demonstrate bidirectional interference, but positive interference is favored under such formats.

Conclusions: Model calculations demonstrate the theoretical basis for bidirectional interference in two-stage immunoassays. Results delineate constraints on conditions in which bidirectional interference can occur.
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http://dx.doi.org/10.1016/j.clinbiochem.2017.08.005DOI Listing
December 2017

Hemoglobin Wayne Trait with Incidental Polycythemia.

Ann Clin Lab Sci 2017 Jan;47(1):96-98

Department of Pathology and Laboratory Medicine, University of Texas Health Science Center-McGovern Medical School, Houston, TX, USA

Hemoglobinopathies, caused by mutations in the globin genes, are one of the most common inherited disorders. Many of the hemoglobin variants can be identified by hemoglobin analysis using conventional electrophoresis and high performance liquid chromatography; however hemoglobin DNA analysis may be necessary in other cases for confirmation. Here, we report a case of a rare alpha chain hemoglobin variant, hemoglobin Wayne, in a 47-year-old man who presented with secondary polycythemia. Capillary zone electrophoresis and high performance liquid chromatography revealed a significant amount of a hemoglobin variant, which was further confirmed by hemoglobin DNA sequencing as hemoglobin Wayne. Since the patient was not homozygous for hemoglobin Wayne, which is associated with secondary polycythemia, the laboratory diagnosis in this case was critical in ruling out hemoglobinopathy as the etiology of his polycythemia.
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January 2017

Morphoproteomics Identifies SIRT1 and EZH2 Pathways as Commonalities in B-cell Acute Lymphoblastic Leukemia: Pathogenetic Implications and Opportunities for Therapeutic Intervention.

Ann Clin Lab Sci 2017 Jan;47(1):3-9

Department of Pathology and Laboratory Medicine, UTHealth, McGovern Medical School, Houston, Texas, USA.

B-cell acute lymphoblastic leukemia (ALL) represents a malignant process in which bone marrow-derived lymphoblasts retain their undifferentiated state. Genetic testing has revealed either no identifiable cytogenetic and genomic abnormalities in such patients or a wide range of aberrations that may or may not contribute to the block in differentiation and the associated proliferation of the malignant lymphoblasts in cases of B-cell ALL. In this study, we applied morphoproteomics to a representative spectrum of cases of newly diagnosed B-cell ALL in order to identify pathways that are known to be associated with the maintenance of the undifferentiated state while promoting proliferation. Our results showed nuclear expression in a majority of the lymphoblasts from bone marrow clot preparations of each of the study cases for both silent mating type information regulation 2 homolog 1 (SIRT1), an NAD+ histone deacetylase and enhancer of Zeste homolog 2 (EZH2), a histone methyltransferase. These represent pathogenetic pathways capable of blocking differentiation and promoting proliferation of the B-cell ALL lymphoblasts. Data mining of the National Library of Medicine's MEDLINE Database and Ingenuity Pathway analysis revealed agents of relatively low toxicity-melatonin, metformin, curcumin and sulforaphane-that are capable of inhibiting directly or pharmacogenomically one or both of the SIRT1 and EZH2 pathways and should, in a combinatorial fashion, remove the block in differentiation and decrease the proliferation of the B-cell ALL lymphoblasts.
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January 2017

Natural Active Ingredients for Diabetes and Metabolism Disorders Treatment.

Evid Based Complement Alternat Med 2016 6;2016:2965214. Epub 2016 Nov 6.

Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX, USA.

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http://dx.doi.org/10.1155/2016/2965214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5116347PMC
November 2016

Comparison of SemiQuantitative Cotinine Values Obtained by the DRI Immunoassay and Values Obtained by a Liquid Chromatography-Tandem Mass Spectrometry-Based Method: The DRI Immunoassay is Suitable for Screening Purposes Only Because Semiquantitative Values May Be Unreliable.

J Clin Lab Anal 2016 Nov 23;30(6):1106-1109. Epub 2016 May 23.

Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, Texas, USA.

Background: DRI cotinine assay is suitable only for screening for cotinine in urine specimens. We studied the reliability of DRI cotinine semiquantitative values by comparing them with the cotinine concentration obtained with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method.

Methods: Semiquantitative cotinine concentrations in 39 urine specimens obtained by the DRI immunoassay were compared with cotinine concentrations obtained by LC-MS/MS.

Results: The DRI cotinine assay consistently overestimated cotinine values obtained by the LC/MS/MS method (y = 1.1529 x + 252.24, n = 39, R = 0.8899) indicating that semiquantitative values obtained using the DRI assay may be unreliable. However, no false-negative results were observed using the DRI assay.

Conclusion: DRI cotinine assay is suitable only for screening cotinine in urine specimens.
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http://dx.doi.org/10.1002/jcla.21988DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6807043PMC
November 2016

Suitability of the DRI Hydrocodone/Hydromorphone Immunoassay in the Clinical Environment at a Lower Cutoff: Validation With LC-MS/MS Analysis.

Ther Drug Monit 2016 12;38(6):787-790

*Physician's Choice Laboratory Services, Rock Hill, SC; and †Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX.

Background: We evaluated the analytical performance of the DRI hydrocodone/hydromorphone assay by comparing semiquantitative values obtained by this assay with values obtained by a liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) method. We also evaluated the possibility of lowering the cutoff of the DRI assay from 300 to 100 ng/mL.

Methods: We compared semiquantitative values obtained by the DRI assay in 97 specimens with values obtained by the LC-MS/MS method including 10 specimens containing hydrocodone and/or hydromorphone concentrations between 105.0 and 145.0 ng/mL (determined by LC-MS/MS) to determine the sensitivity at 100 ng/mL. In addition, several opioids at a concentration of 5000 ng/mL were also analyzed by the DRI assay to determine its specificity.

Results: We observed no false-negative result using the DRI immunoassay in 96 specimens that showed semiquantitative values at 100 ng/mL or higher. However, one specimen containing 110 ng/mL of hydrocodone was false negative with the DRI assay (semiquantitative value 88 ng/mL, below 100 ng/mL cutoff). The semiquantitative values produced by DRI showed poor correlation with values determined by the LC-MS/MS method. The sensitivity of the DRI assay at 100 ng/mL was 90%, and the assay was very specific showing minimal cross-reactivity only with oxycodone and oxymorphone.

Conclusions: DRI immunoassay for hydrocodone/hydromorphone is a cost-effective method of screening urine specimens in the clinical environment at a lower cutoff of 100 ng/mL.
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http://dx.doi.org/10.1097/FTD.0000000000000339DOI Listing
December 2016

Effect of Carbamazepine 10, 11-Epoxide on Serum Carbamazepine Measurement Using a New CMIA Assay: Comparison of Values Obtained by Using PETINIA, CEDIA and Liquid Chromatography Combined with Tandem Mass Spectrometry.

Ann Clin Lab Sci 2016 May;46(3):242-6

ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, and Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT, USA.

Background: Carbamazepine is a classical anticonvulsant that requires therapeutic drug monitoring. We evaluated the effect of carbamazepine 10, 11 epoxide on a new chemiluminescent immunoassay (CMIA) for application on the Architect i1000SR analyzer.

Materials And Methods: Carbamazepine concentrations were measured in 40 specimens collected from patients taking carbamazepine using a PETINIA assay (Vista 1500 analyzer), a CEDIA assay (Cobas c501 analyzer) and the new CMIA assay (Architect i1000 analyzer). In addition, carbamazepine and carbamazepine 10, 11-epoxide concentrations were determined using a reference liquid chromatography combined with a tandem mass spectrometry (LC/MS/MS) reference method in another 15 specimens. These specimens were further analyzed using the PETINIA, CEDIA and CMIA assays.

Results And Discussion: A good correlation (regression equation: y = 0.9605x+0.2788, n=40, r=0.98) between values obtained by using the CEDIA assay (x-axis) and the CMIA assay (y-axis) was observed but the PETINIA assay showed significant bias compared to the CMIA assay (regression equation: y=0.8191x+0.3069, n=40, r=0.97). The bias was due to high cross-reactivity of epoxide with the PETINIA assay as revealed by comparing carbamazepine values obtained by LC-MS/MS with these three assays.

Conclusions: The new CMIA assay is suitable for therapeutic drug monitoring of carbamazepine because values correlated well with the CEDIA assay values (n=40) as well as LC-MS/MS reference method values in 15 specimens.
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May 2016

Analytical Performance Evaluation of a New Cobas Tacrolimus Assay on Cobas e411 Analyzer: Comparison of Values Obtained by the CMIA Tacrolimus Assay and a Liquid Chromatography Combined with Tandem Mass Spectrometric Method.

Ann Clin Lab Sci 2016 ;46(2):204-8

ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT and Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT, USA.

Background: Recently Roche Diagnostics (Indianapolis, IN) developed Cobas tacrolimus assay (currently for investigational use only in U.S) for application on multiple platforms including Cobas e 411 analyzer. We evaluated analytic performance of this new assay.

Materials And Methods: Within run, between run and linearity of this new assay were evaluated. In addition, tacrolimus values in 40 specimens obtained by using this new method were compared with values obtained by using the CMIA assay (Abbott Laboratories). Moreover, 10 specimens where accurate tacrolimus values were determined by a reference method (LC-MS/MS), were further analyzed using Cobas tacrolimus assay and the CMIA assay.

Results: New Cobas tacrolimus assay showed excellent precision and accuracy. Comparing tacrolimus values obtained by using the CMIA tacrolimus assay (x-axis) with corresponding values obtained by using the Cobas tacrolimus assay (y-axis), the following regression equation was observed: y=0.922x+0.512 (n=40, r=0.99). For additional 10 specimens where tacrolimus values were determined by LC-MS/MS, tacrolimus values obtained by the Cobas tacrolimus assay as well as by the CMIA assay were higher than the corresponding LC-MS/MS values.

Conclusions: The new Cobas tacrolimus assay is comparable to the FDA approved CMIA tacrolimus assay. Therefore, when this assay is approved by the FDA, it can be used for therapeutic drug monitoring of tacrolimus.
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January 2017

Bioinformatics Analysis to Determine Prognostic Mutations of 72 de novo Acute Myeloid Leukemia Cases from the Cancer Genome Atlas (TCGA) with 23 Most Common Mutations and no Abnormal Cytogenetics.

Ann Clin Lab Sci 2015 ;45(5):515-21

Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA

Objectives: Up to 40% of acute myeloid leukemia (AML) patients have normal cytogenetics (CN-AML) but they may have gene mutations. An important issue in the treatment of CN-AML is how gene mutation patterns may help with patient management. The Cancer Genome Atlas (TCGA) database has data from 200 cases of de novo AML including cytogenetics, gene mutations, and survival duration (prognosis).

Methods: Cases with the most common mutations and no cytogenetic abnormalities were selected from the TCGA. Unsupervised neural network analysis was performed to group them into clusters according to their pattern of mutations and survival.

Results: 72 cases of CN-AML with the 23 most common mutations were obtained from TCGA. Clustering was found to be based on 6 mutations, with the following prognostic groups: (a) good: NPM1, CEBPA, or TET2, (b) intermediate: NPM1/DNMT3A, or other mutations, (c) poor: RUNX1, FLT3-ITD, FLT3-ITD/NPM1, or FLT3-ITD/CEBPA. Some discrepancy between our results and those from previous studies is most likely due to inclusion of AML cases transformed from myeloproliferative neoplasms or myelodysplastic syndrome in previous studies.

Conclusions: This study provides further molecular characterization and prognostic data most specific for the de novo subgroup of CN-AML patients.
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October 2016

Utility of VerifyNow for Point-of-Care Identification of an Aspirin Effect Prior to Emergency Cardiac Surgery.

Ann Clin Lab Sci 2015 ;45(4):377-81

Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX, USA

Background: Patients with cardiovascular disease are frequently on aspirin, which may place them at risk for bleeding during surgical procedures. The utility of the VerifyNow test to rapidly identify an aspirin effect and predict bleeding risk prior to cardiac surgery was explored.

Methods: A retrospective study was performed of patients on a clinical pathology consultation service that provides laboratory and transfusion support for patients undergoing major cardiac surgery. Patients who had VerifyNow testing for aspirin effect were selected.

Results: A total of 88 patients had VerifyNow aspirin testing during the study period. The VerifyNow test correctly identified 52/63 (82.5%) patients with documented aspirin use, and missed 11/63 (17.5%) of aspirin users. Light transmission aggregometry (LTA) showed an aspirin effect in the majority of aspirin users missed by the VerifyNow assay. Moderate correlations were found between LTA and VerifyNow. Low aspirin reaction units were not associated with significant bleeding in these cardiac surgery patients.

Conclusions: We propose the VerifyNow assay for point-of-care identification of aspirin effect prior to emergency surgeries.
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May 2016

The iDigoxin Assay is More Sensitive than LOCI Digoxin Assay for Rapid Detection of Convallatoxin, the Active Cardiac Glycoside of Lily of The Valley.

Ann Clin Lab Sci 2015 ;45(3):323-6

Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston TX, USA

Objective: Lily of the valley is a poisonous plant due to the presence of the cardiac glycoside convallatoxin. We compared two immunoassays (LOCI digoxin assay and iDigoxin assay) for rapid detection of convallatoxin if present in human serum.

Materials And Methods: Aliquots of a drug free serum pool and a digoxin serum pool were supplemented with microliter amounts of lily of the valley extract or nanogram to microgram quantities of convallatoxin, followed by measurement of apparent digoxin concentrations using the LOCI and iDigxoin assays.

Results: Apparent digoxin concentrations were observed when aliquots of a drug free serum pool were supplemented with convallatoxin or lily of the valley extract using both assays but apparent digoxin concentrations were significantly higher using the iDigoxin assay. In addition, the interference of convallatoxin in serum digoxin measurement was also significantly higher using iDigxoin assay compared to the LOCI digoxin assay.

Conclusions: The iDigxoin assay is more sensitive in detecting convallatoxin in human serum.
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March 2016

Comparison of Response of DRI Oxycodone Semiquantitative Immunoassay With True Oxycodone Values Determined by Liquid Chromatography Combined With Tandem Mass Spectrometry: Sensitivity of the DRI Assay at 100 ng/ml Cut-Off and Validity of Semiquantitative Value.

J Clin Lab Anal 2016 May 25;30(3):190-5. Epub 2015 Feb 25.

Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, Texas.

Objective: Oxycodone is a widely used opioid for pain management and patient's compliance with therapy is often monitored by using oxycodone immunoassay. The performance of the DRI oxycodone immunoassay was compared with liquid chromatography combined with tandem mass spectrometry (LC/MS/MS) assay.

Materials And Methods: In 48 urine specimens collected from patients taking oxycodone, urinary oxycodone concentrations were determined using LC/MS/MS and the DRI oxycodone immunoassay for application on the Cobas c 501 analyzer (Roche Diagnostics, Indianapolis, IN).

Results: Out of 48 specimens, 14 specimens showed oxycodone value less than 100 ng/ml, seven specimens had low positive values (between 101 and 165 ng/ml) and all other specimens had values 165 to 1789 ng/ml using the LC/MS/MS assay. The DRI oxycodone assay successfully identified all oxycodone specimens with oxycodone concentrations over the 100 ng/ml. In addition, the DRI assay also showed positive response in 11 out of 14 specimens with oxycodone values less than 100 ng/ml. However, semiquantitative values obtained by the DRI assay did not match with true oxycodone and metabolite oxymorphone concentrations combined obtained by using LC/MS/MS.

Conclusions: DRI oxycodone immunoassay at 100 ng/ml is a reliable immunoassay for analysis of oxycodone in urine.
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http://dx.doi.org/10.1002/jcla.21834DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6807119PMC
May 2016

Prevalence of Howell-Jolly body-like inclusions in HIV patients and their correlation with CD4 counts and HIV RNA viral load.

Ann Clin Lab Sci 2015 ;45(1):23-6

Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at Houston, Houston, TX, USA

Previous reports have described the rare occurrence of detached nuclear fragments resembling Howell-Jolly bodies within neutrophils from HIV patients, organ-transplant recipients, and patients on immunosuppressive drugs. To date, their potential clinical significance is unknown, and pathologists tend to disregard their presence. Our study sought to find a correlation between these inclusions and the overall disease state, specifically within the HIV patient population. Eighty-three peripheral smears, all from different patients, were examined for the presence of inclusions and compared with recent CD4 counts and HIV RNA viral loads. Six cases contained inclusions, yielding a prevalence of 7.2%. These six patients had a mean CD4 count of 546±305 cells/μL compared to 247±242 cells/μL in those lacking inclusions (p<0.006) and viral loads of 1,686±3,446 copies/mL compared to 241,882±1,137,229 copies/mL in those lacking inclusions (p=0.6). These findings indicate that the presence of Howell-Jolly body-like inclusions may be viewed as a potential biomarker indicative of a low risk for disease progression and/or good response to therapy based upon higher CD4 counts and relatively favorable viral loads.
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December 2015

Zinc Sulfate, a Recently Introduced Urinary Adulterant Can Invalidate Urine Cotinine Test Using Immunoassay but Has Less Effect on Liquid Chromatography Combined With Tandem Mass Spectrometry-Based Test.

Ther Drug Monit 2015 Oct;37(5):681-4

*Physician's Choice Laboratory Services, Rock Hill, South Carolina; and †Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston.

Objective: Zinc sulfate is a recently introduced urinary adulterant, which causes false-negative results with immunoassays used for screening drugs of abuse in urine but whether zinc sulfate also could invalidate urine cotinine assay using immunoassay or liquid chromatography combined with mass spectrometry has never been studied.

Design And Method: Four urine pools containing none detected to high levels of cotinine were analyzed using DRI cotinine immunoassay on the Olympus 640 analyzer as well as using liquid chromatography combined with tandem mass spectrometry. Specimens were reanalyzed after supplementing with various amounts of zinc sulfate that are known to invalidate immunoassays used for drugs of abuse testing.

Results: Zinc sulfate in all concentrations studied caused false-negative results using immunoassays, but zinc sulfate also reduced cotinine values by approximately 2.1%-38.4% when analyzed using liquid chromatography combined with mass spectrometry.

Conclusions: Zinc sulfate caused false-negative cotinine result when DRI immunoassay was used and also had small to moderate impact on liquid chromatography combined with tandem mass spectrometry-based assay for urine cotinine.
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http://dx.doi.org/10.1097/FTD.0000000000000186DOI Listing
October 2015

Thromboelastography is a suboptimal test for determination of the underlying cause of bleeding associated with cardiopulmonary bypass and may not predict a hypercoagulable state.

Am J Clin Pathol 2014 Oct;142(4):492-7

From the Department of Pathology and Laboratory Medicine, University of Texas at Houston.

Objectives: Patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at risk of bleeding. The goal of this investigation was to compare thromboelastography (TEG) with standard coagulation tests (prothrombin time [PT], partial thromboplastin time [PTT], fibrinogen, and D-dimer) in patients with active bleeding.

Methods: A retrospective study of patients who underwent cardiac surgery with CPB was performed. A second analysis was performed to determine if a shortened TEG R time is associated with thrombosis.

Results: Paired TEG and standard coagulation tests were available from 21 bleeding patients; of the 15 patients with normal TEG values and three with a shortened R time, all had abnormalities of standard coagulation tests. Eighteen of 67 patients who underwent surgery with CPB had an episode of postoperative bleeding. The TEG R time and coagulation index, PT, and PTT collected after CPB were associated with postoperative bleeding in the univariate analysis, but only PT was independently associated with postoperative bleeding in the multivariate analysis. In the second analysis, three of 38 patients with a normal TEG and four of 43 patients with a shortened R time had a thrombotic event during hospitalization (P = 1.00).

Conclusions: TEG had limited utility in identifying the underlying cause of bleeding and was not predictive of postoperative bleeding associated with cardiac surgery compared with conventional coagulation tests. A shortened TEG R time may not represent a hypercoagulable state.
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http://dx.doi.org/10.1309/AJCPVB73TMIDFNCBDOI Listing
October 2014

Inability to Measure M-Protein With Capillary Zone Electrophoresis (CAPPILLARYS 2) in Tracings With NonDiscernable Peaks.

J Clin Lab Anal 2015 Sep 17;29(5):343-6. Epub 2014 Aug 17.

Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, Texas.

Background: We performed a retrospective study to illustrate the challenges with quantifying monoclonal (M)-protein in the cases of serum protein capillary zone electrophoresis (SPCZE) where no discernable peak is apparent.

Materials And Methods: We retrospectively reviewed 160 serum immunofixation electrophoresis (SIFE) that were performed at Memorial Hermann Hospital-Texas Medical Center between October 2013 and November 2013 and we identified the positive SIFE results. The corresponding SPCZE of the positive SIFE were retrieved and evaluated for the ability to quantify M-proteins in them. We define the ability to quantify M-protein as the ability for the operator of the SPCZE to identify a discernable peak and to be able to manually gate the area under the peak.

Results: Twenty-two cases of SIFE detected a monoclonal immunoglobulin. Of the corresponding 22 SPCZE, we could not quantify the M-protein in 6 (27.3%) of the cases.

Conclusion: We have shown several cases where we were not able to quantify the M-protein with SPCZE. This poses a challenge in the diagnosis and management of these patients.
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http://dx.doi.org/10.1002/jcla.21776DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6807229PMC
September 2015

Rapid detection of the active cardiac glycoside convallatoxin of lily of the valley using LOCI digoxin assay.

Am J Clin Pathol 2014 Sep;142(3):307-12

From the Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston.

Objectives: To explore the luminescent oxygen channeling technology-based digoxin immunoassay (LOCI digoxin assay) for rapid detection of lily of the valley extract and convallatoxin. The potential in vitro binding of convallatoxin with Digibind was also evaluated.

Methods: Aliquots of a drug-free serum pool and a digoxin serum pool were supplemented with lily of the valley extract or convallatoxin, and then apparent digoxin concentrations were measured using the LOCI digoxin assay. Mice were administered lily of the valley extract or 50 μg of convallatoxin, and digoxin concentrations in serum specimens were measured 1 and 2 hours after gavage. Aliquots of a serum pool supplemented with convallatoxin or lily of the valley extract were further supplemented with various concentrations of Digibind and free apparent digoxin concentrations were measured.

Results: Apparent digoxin concentrations were observed when aliquots of a drug-free serum pool were supplemented with convallatoxin or lily of the valley extract, and also with convallatoxin or herbal extract. Bidirectional interference of convallatoxin and lily of the valley extract with serum digoxin measurement using the LOCI assay was also observed. Digibind was capable of binding convallatoxin in vitro.

Conclusions: LOCI digoxin assay can be used for rapid detection of convallatoxin, and Digibind can bind convallatoxin in vitro.
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http://dx.doi.org/10.1309/AJCPCOXF0O5XXTKDDOI Listing
September 2014

Higher sensitivity of capillary electrophoresis in detecting hemoglobin A2'compared to traditional gel electrophoresis.

Ann Clin Lab Sci 2014 ;44(3):291-3

Department of Pathology at University of Texas Health Science Center at Houston. Houston, Texas, USA

HbA2' (also called Hb B2) is the most common delta-globin chain defect and is reported to occur in 1-2% of the African American population. The major clinical significance of HbA2' is that the failure to detect it might lead to an underestimation of the total HbA2, leading to failure to diagnose β-thalassemia minor. In order to diagnose β-thalassemia minor, both HbA2 and HbA2' levels must be combined.Hb A2' accounts for a small percentage (1-2%) of the total hemoglobin in heterozygotes. It is difficult to detect this small amount by traditional gel electrophoresis. Using HPLC Hb A2' is easily detected as it produces a minor peak in the S window. Other conditions which might interfere with detection of HbA2' by HPLC include Hb S trait or Hb SS disease (Hb A2' hidden in the S peak), transfused Hb SS (Hb S peak may be very small), Hb C trait or Hb CC disease (glycosylated Hb C elutes in the S window), and Hb G (Hb G2 elutes in the S window). All of the above conditions, including Hb A2', occur most commonly in the same ethnic group (African American). We reviewed 654 consecutive cases over a period of three months for the presence of Hb A2' in our laboratory where capillary electrophoresis is used as the primary diagnostic tool. We detected seven cases (1.07 %) of HbA2'. In contrast, we did not detect any HbA2' using conventional gel electrophoresis in the last one year (2,580 cases). Although in none of the seven cases the sum of Hb A2 and Hb A2' exceeded 3.5%, we believe that capillary electrophoresis allows for a better detection of Hb A2' than gel electrophoresis and HPLC.
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May 2015