Publications by authors named "Soo Jin Yoo"

40 Publications

Performance of Norudia Glycated Albumin Assay on Multiple Analytical Platforms and Comparison to Lucica Assay.

Clin Lab 2020 Nov;66(11)

Background: The Norudia glycated albumin (GA) assay was evaluated for analytical performance and assay applicability on multiple analytical platforms.

Methods: The evaluation included precision, linearity, reference interval, and comparison with Lucica GA assay. A multicenter study was conducted to compare the results of Norudia GA assay on five kinds of widely used automated clinical chemistry analyzers.

Results: Within-laboratory imprecisions for GA% presented 1.3 - 3.3% and 0.8 - 2.6% for low- and high-level control materials, respectively, on different analyzers. GA assay was linear from 20.0 to 680.0 µmol/L of GA. The claimed reference range (12 - 16 GA%) was verified. Norudia GA showed a good GA% correlation with Lucica GA (correlation coefficient 0.999). GA% from each analyzer showed good correlation with the consensus mean of the results of five analyzers (correlation coefficient 0.997 - 0.999).

Conclusions: The Norudia GA assay can successfully be implemented in all the tested platforms, with good GA% correlation.
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http://dx.doi.org/10.7754/Clin.Lab.2020.200107DOI Listing
November 2020

Somatic Mosaicism of NF2 Gene Mutation with Constitutional NF1 Gene Mutation in Neurofibromatosis Type 2: a Case Report.

Clin Lab 2020 Nov;66(11)

Background: Neurofibromatosis (NF) is a genetic disorder, and neurofibromatosis types 1 and 2 have different genetic and clinical features. Herein, we present the clinical and genetic aspects of a patient carrying a constitutional NF1 gene mutation and whose neurocutaneous manifestations suggested a NF type 2 (NF2).

Methods: A 55-year-old woman presented with headache and deterioration of vision. Physical examination and radiologic findings revealed multiple subcutaneous nodules and multiple intracranial and spinal masses which were suspected to be NF2.

Results: Genomic DNA sequencing using a peripheral blood sample revealed a splicing mutation in the NF1 gene. Tumor resection and biopsy revealed intracranial meningiomas and paraspinal Schwannoma compatible with NF2. PCR-direct sequencing using tumor tissue samples showed pathogenic somatic mutation of the NF2 gene.

Conclusions: We report a case of NF2 presenting with a pathogenic somatic mutation in the NF2 gene in a woman harboring a germline splicing mutation in the NF1 gene. This case emphasizes the importance of sequence analy¬sis by using tumor tissues and the need to elucidate the role of a NF1 splicing mutation.
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http://dx.doi.org/10.7754/Clin.Lab.2020.200403DOI Listing
November 2020

Importance of Susceptibility Rate of 'the First' Isolate: Evidence of Real-World Data.

Medicina (Kaunas) 2020 Sep 28;56(10). Epub 2020 Sep 28.

Laboratory Medicine, Inje University, Ilsan Paik Hospital, Goyang 10380, Korea.

For proper antimicrobial therapy, cumulative antibiograms should be representative of geographic region and be accurate. Clinical and Laboratory Standards Institute (CLSI) guidelines recommend that only the first isolates (FI) of a species per patient are used when reporting cumulative antibiograms. However, >50% of hospitals in the United States report antibiograms of all isolates. We compared antibiograms from the FI with those from total isolates (TI). Antimicrobial data of all isolates identified in the Microbiology unit of Ilsan Paik Hospital in 2019 were retrospectively acquired from the hospital information system. The susceptibility rates to antimicrobials of , , , , , , and were analyzed by FI and TI, respectively. Isolate counts and susceptibility rates of each species for the reported antimicrobials were compared. The numbers of isolates by FI/TI were as follows: 1824/2692 , 480/1611 , and 662/1306 , and 407/953 for gram-negative bacteria and 649/1364 , 211/313 , and 323/394 for gram-positive bacteria. All antimicrobial agents showed higher susceptibility rates when calculated as FI than as TI in gram-negative bacteria except colistin: 3.7% for , 14.5% for , 8.3% for , and 7.9% for . In , 8/11 antimicrobial agents revealed higher susceptibility rates for FI than for TI. and showed lower susceptibility rates for 7/10 antimicrobial agents for FI than for TI. The oxacillin susceptibility rates of were 36.6%/30.2% with FI/TI and vancomycin susceptibility rates for were 54.1% and 49.5%, respectively. When comparing cumulative antibiograms by FI with TI using real-world data, there is a large gap for critical species requiring hospital infection control. Although FI calculation is difficult, antibiograms must be calculated as FI for proper preemptive antimicrobial therapy because FI provides proper antimicrobial susceptibility data.
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http://dx.doi.org/10.3390/medicina56100507DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600976PMC
September 2020

Preanalytical Errors in the Central Laboratory of a University Hospital Based on the Analysis of Year-Round Data.

Clin Lab 2020 Sep;66(9)

Background: Preanalytical errors cause a decrease in the accuracy of clinical laboratory results. We analyzed preanalytical errors (preAEs) made in the clinical laboratory of a university hospital.

Methods: All samples received in a centralized laboratory from January 1, to December 31, 2018, were analyzed retrospectively. The categories of preAEs were improper request, incorrect labeling, improper collection/transport, inadequate sample volume, inappropriate container, hemolysis, and sample clotting. The rates of preAEs in these categories were calculated according to sample type, laboratory subunit, department, sampling place, sampling time, and patient age.

Results: Of 1,082,014 samples received and analyzed by the laboratory, 6,848 (0.63%) were classified as having preAEs. The most frequent categories of preAE were hemolysis (44.6%), sample clotting (30.8%), and inadequate volume (16.7%). The most frequent preAE category for whole-blood and serum/plasma was clotting and hemolysis, respectively. The most frequent preAE category in the blood bank, clinical chemistry, immunology, and test referral service laboratory subunits was hemolysis, in the hematology subunit it was sample clotting, and in the microbiology and urinalysis subunits it was inadequate sample volume. Surgical departments had a higher rate of preAEs than did non-surgical departments (p < 0.0001). Samples drawn in the sampling room showed the lowest frequencies of preAEs (0.01%). Samples drawn on general wards from 5 pm to 5 am, when duty nurses perform sampling, showed a preAE rate of 2.80%. The rate of preAEs increased with patient age.

Conclusions: This analysis of preAEs is the most comprehensive to date. Our findings will promote the provision of high-quality laboratory services to clinicians and their patients.
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http://dx.doi.org/10.7754/Clin.Lab.2020.200110DOI Listing
September 2020

Clinical Utility of HIV-1/2 Ab Immunochromatographic Assay as an Additive Test for HIV Screen-Positive Patients.

Authors:
Soo Jin Yoo

Ann Clin Lab Sci 2020 Mar;50(2):274-277

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea

Objective: Frequent false-positive results of current HIV screening occur due to its high sensitivity. These false-positives may delay subsequent clinical decision making. In this study, we aim to determine the usefulness of additional immunochromatographic assay (ICA) in hospitals using fourth-generation HIV-1/2 Ag/Ab assays followed by western blot (WB) confirmation.

Methods: Overall, 158,431 patients' sera were screened for HIV using a fourth-generation HIV-1/2 Ag/Ab assays (Elecsys HIV combiPT) from July 2011 to May 2019. All 401 ECLIA-positive sera were re-tested using an ICA kit (SD Bioline HIV1/2 3.0 ICA), followed by WB confirmation according to national policy.

Results: Sixty-five ECLIA-positive samples (65/401, 16.2%) were positive for ICA, 96.9% (63/65) of which were confirmed positive using WB. ICA results were negative in 83.8% (336/401) of ECLIA-positive samples, of which 98.5% (331/336) remained negative on WB. Five specimens (1.5%) from patients with symptoms consistent with acute HIV syndrome were false negatives on ICA. These false negatives were confirmed positive using a p24 antigen assay and nucleic acid test (NAT).

Conclusions: ICA for anti-HIV Ab screen-positive specimens is helpful for earlier medical decision considering frequent false-positive results on screening. Nonetheless, ICA might be negative in acute HIV syndrome, necessitating p24 Ag assay or NAT with shorter window periods.
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March 2020

Real-time display of laboratory testing status improves satisfaction levels in an emergency department: A pilot study.

J Clin Lab Anal 2020 Jul 9;34(7):e23290. Epub 2020 Mar 9.

Laboratory Medicine, Inje University, Sanggye Paik Hospital, Seoul, Korea.

Background: Clinicians need to know timelines of requested laboratory tests to provide effective patient management. We developed a real-time laboratory progress checking system and measured its effectiveness using appropriate indicators in an emergency room setting.

Methods: In our original in-house health information system display, blank spaces, which were generated for test results when tests were ordered, remained empty until the final results reported. We upgraded the laboratory reporting system to show real-time testing information. The stages included requests for test, label printing, sampling, laboratory receipts, performance of tests, verification of results, and interpretation of results and final report by laboratory physician. To assess the usefulness of the function, we measured the emergency department healthcare workers' satisfaction and compared the number of phone calls about test status before and after implementation.

Results: After the system upgrade, the healthcare workers' understanding of the testing process increased significantly as follows. More clinicians could estimate the time of final test results through the real-time testing status information (61.9% and 85.7%, P = .002), and respondents reported that the upgraded system was more convenient than the original system (41.3% and 22.2%, respectively, P = .022). The number of phone calls about the test status decreased after implementation of the upgrade; however, the difference was not statistically significant (before, 0.13% [63 calls/48 637 tests] and after, 0.09% [42/46 666]; P = .066).

Conclusions: The real-time display of laboratory testing status increased understanding of testing process among healthcare workers in emergency room, which ultimately may increase the usefulness and efficiency of the laboratory service use.
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http://dx.doi.org/10.1002/jcla.23290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7370723PMC
July 2020

Evaluation of the new Beckman Coulter Access hsTnI: 99th percentile upper reference limits according to age and sex in the Korean population.

Clin Biochem 2020 May 12;79:48-53. Epub 2020 Feb 12.

Health Promotion Center and Department of Family Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Republic of Korea.

Background: Defining the 99th percentile upper reference limits (URL) of cardiac troponin I (cTnI) is critical because it is clinically important in determining myocardial injury, and is variable among reagents, age, sex, or races. The analytical performance of the new, high- sensitivity reagent Beckman Coulter Access hsTnI was evaluated, and its 99th percentile URL was determined in the Korean population.

Methods: Analytical performances of Access hsTnI assay were evaluated including imprecision and limit of measurements. To define the reference limits, 600 healthy subjects were included with similar proportions of sex and age groups.

Results: Beckman Coulter Access hsTnI assay presented a limit of blank, detection, and quantitation at 10% CV of 0.32 ng/L, 0.63 ng/L, and 6.1 ng/L, respectively, and 98.3% of the healthy population showed cTnI above the limit of detection. The 99th percentile URLs were 9.5 ng/L (90% CI 7.4-14.9), 7.8 ng/L (90% CI 5.5-19.2 ng/L), and 11.3 ng/L (90% CI 8.0-15.7 ng/L) in 600 healthy participants, 300 women and 300 men, respectively with imprecision less than 10% CV. The median values and 99th percentile URLs of hsTnI were higher in men and the age group ≥50 years than in women and the age group <50 years, respectively.

Conclusions: Access hsTnI assay met the performance criteria of the IFCC for high-sensitivity cTnI assays. Their 99th percentile URLs in the Korean population were lower than the manufacturer's claims. cTnI values were significantly different among different sex and age groups.
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http://dx.doi.org/10.1016/j.clinbiochem.2020.02.005DOI Listing
May 2020

Different parental origins of supernumerary X chromosomes in brothers with Klinefelter syndrome: A case report.

Medicine (Baltimore) 2019 Nov;98(44):e17838

Laboratory Medicine, Sanggye Paik Hospital, Inje University, College of Medicine, Seoul, Republic of Korea.

Rationale: Recurrence of Klinefelter syndrome (KS) in non-twin brothers is very rare. This study examined the inheritance pattern of supernumerary X chromosomes in non-twin brothers.

Patient Concerns: A 16-year-old man presented with small-sized testicles. During his diagnostic work-up, his brother, in his late 20's, also complained of small testes and erectile dysfunction.

Diagnosis: Chromosome analysis in peripheral blood revealed non-mosaic 47,XXY karyotype in both brothers. Their mother showed a normal 46,XX karyotype.

Interventions: To examine the inheritance pattern of supernumerary X chromosomes, quantitative-fluorescence PCR was performed with small tandem repeat markers. It revealed that their supernumerary X chromosomes were inherited from different parents.

Outcomes: After the diagnosis of KS, 2 brothers started to receive testosterone treatment.

Conclusion: This case report is the first to report differences in the origins of supernumerary X chromosomes in brothers with KS and furthers the current understanding of the cytogenetic mechanisms in KS.
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http://dx.doi.org/10.1097/MD.0000000000017838DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946345PMC
November 2019

Hypoglycemic potential of whole green tea: water-soluble green tea polysaccharides combined with green tea extract delays digestibility and intestinal glucose transport of rice starch.

Food Funct 2019 Feb;10(2):746-753

Vital Beautie Research Institute, AMOREPACIFIC R&D Center, Yongin-si, Gyeonggi-do 17074, Republic of Korea.

Green tea is being studied extensively for its postprandial hypoglycemic effect due to its abundant catechins. Along with catechins, water-soluble green tea polysaccharides are also currently gaining attention due to their natural hypoglycemic properties. The current study investigated the combinational effect of green tea extract (GTE) and crude green tea polysaccharides (CTP) in inhibiting glucose transport after digestion of rice starch, using an in vitro digestion model with a Caco-2 cell. Co-digestion of rice starch with GTE (16.09 ± 1.02 g L-1), CTP (16.83 ± 0.81 g L-1), or GTE + CTP (17.79 ± 0.80 g L-1) hydrolyzed less starch into glucose compared with the control (18.24 ± 0.45 g L-1). Glucose transport from digesta to the Caco-2 cell after 120 min incubation was significantly inhibited with GTE + CTP (53.26 ± 4.34%). Gene expression of intestinal glucose transporters, which included sodium-dependent glucose transporter (SGLT1) and glucose transporter 2 (GLUT2), was not altered by GTE, CTP or GTE + CTP, except for the GTE-mediated upregulation of GLUT2. It is concluded that GTE + CTP lowered digestibility of rice starch with glucose and also delayed glucose uptake to the intestinal epithelium. This finding suggests a potential for green tea polysaccharides as a natural postprandial hypoglycemic substance.
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http://dx.doi.org/10.1039/c8fo01936cDOI Listing
February 2019

Kallmann syndrome with a Tyr113His PROKR2 mutation.

Medicine (Baltimore) 2017 Sep;96(35):e7974

Department of Internal Medicine, Sanggye Paik Hospital, College of Medicine, Inaja University, Seoul Green Cross Genome, Yongin Cardiovascular and Metabolic Disease Center, College of Medicine, Inje University, Busan Department of Laboratory Medicine, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Republic of Korea.

Rational: Kallmann syndrome (KS) is a genetic gonadotropin-releasing hormone deficiency associated with hyposmia or anosmia and characterized by various modes of inheritance.

Patient Concerns: A 16-year-old male did not reach puberty and was associated with hypogonadotropic hypogonadism and anosmia. His magnetic resonance imaging of brain revealed the absence of the olfactory bulb.

Diagnosis: His karyotype was 46 XY. Sanger sequencing of the KAL1 gene revealed no mutations. Diagnostic exome sequencing identified a prokineticin-receptor 2 (PROKR2) gene variant, c.337T > C (p.Tyr113His), previously reported to be a pathogenic mutation; we confirmed the presence of the mutation via Sanger sequencing of the coding exons of PROKR2. His apparently unaffected mother and sister, but not his father, were heterozygous for the PROKR2 Tyr113His mutation.

Lessons: This work advances our understanding of the role played by PROKR signaling and the mode of inheritance of the gene in patients with KS.
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http://dx.doi.org/10.1097/MD.0000000000007974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5585527PMC
September 2017

Evaluation of the Elecsys(®) Anti-HCV II assay for routine hepatitis C virus screening of different Asian Pacific populations and detection of early infection.

J Clin Virol 2015 Mar 30;64:20-7. Epub 2014 Dec 30.

Peking University People's Hospital, Peking University Hepatology Institute, Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases, Xizhimen South Street No 11, Xicheng District, Beijing 100044, China. Electronic address:

Background: Early diagnosis of hepatitis C virus (HCV) infection is essential to allow appropriate treatment and prevent transmission.

Objectives: To evaluate the Elecsys(®) Anti-HCV II assay as a routine screening assay in Asia using a large number of samples from different Asian Pacific populations and compare its performance with other HCV assays routinely used in the region.

Study Design: The sensitivity and specificity of the Elecsys(®) Anti-HCV II assay were determined using routine hospital samples and compared with at least one of the following comparator assays at nine independent centers: ARCHITECT™ Anti-HCV; Serodia(®)-HCV Particle Agglutination; Vitros(®) ECi Anti-HCV; Elecsys(®) Anti-HCV; ADVIA Centaur(®) HCV; InTec(®) HCV EIA; or Livzon(®) Anti-HCV. Commercially available seroconversion panels were used to assess sensitivity for early detection of infection.

Results: The Elecsys(®) Anti-HCV II assay was more sensitive in recognizing early infection and detected acute HCV infection earlier on average than the comparator assays for all six panels tested. 7,726 routine samples were tested and 322 identified as HCV positive. Elecsys(®) Anti-HCV II had a sensitivity of 100% and a specificity of 99.66%, both of which were comparable or superior to the results obtained for competitor assays, which ranged from 87.5-100% and 98.98-100%, respectively.

Conclusions: The Elecsys(®) Anti-HCV II assay has the sensitivity and specificity to support its use as a routine screening method in the Asia Pacific region. Furthermore, this assay shortens the diagnostic window between infection and the detection of antibodies compared with established methods.
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http://dx.doi.org/10.1016/j.jcv.2014.12.015DOI Listing
March 2015

Single-nucleotide polymorphism PCR for the detection of Mycoplasma pneumoniae and determination of macrolide resistance in respiratory samples.

J Microbiol Methods 2014 Jul 26;102:32-6. Epub 2014 Apr 26.

Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address:

The aim of this study was to develop a single-nucleotide polymorphism (SNP) PCR assay to be performed directly on respiratory samples for the simultaneous detection of Mycoplasma pneumoniae and its 23S rRNA gene mutations, which are responsible for macrolide resistance. For multiplex SNP PCR, two outer primers for amplification of the 23S rRNA gene and two mutant-specific primers for the discrimination of single base changes were designed. A total of 73M. pneumoniae-positive samples and 100M. pneumoniae-negative samples were analyzed using this assay. By SNP PCR, we detected two mutations conferring high-level macrolide resistance in 22 samples (A2063G from 20 and A2064G from 2 samples); these results are identical to those produced by the 23S rRNA gene sequencing of M. pneumoniae-positive samples. Thus, this assay can be used as a practical method for the simultaneous detection of M. pneumoniae and mutations associated with macrolide resistance directly from respiratory samples.
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http://dx.doi.org/10.1016/j.mimet.2014.04.009DOI Listing
July 2014

Performance evaluation of ExiStation HBV diagnostic system for hepatitis B virus DNA quantitation.

J Virol Methods 2013 Nov 25;193(2):492-7. Epub 2013 Jul 25.

Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Republic of Korea.

The performance of a recently developed real-time PCR system, the ExiStation HBV diagnostic system, for quantitation of hepatitis B virus (HBV) in human blood was evaluated. The detection limit, reproducibility, cross-reactivity, and interference were evaluated as measures of analytical performance. For the comparison study, 100 HBV-positive blood samples and 100 HBV-negative samples from Korean Blood Bank Serum were used, and the results of the ExiStation HBV system showed good correlation with those obtained using the Cobas TaqMan (r2=0.9931) and Abbott real-time PCR systems (r2=0.9894). The lower limit of detection was measured as 9.55 IU/mL using WHO standards and the dynamic range was linear from 6.68 to 6.68×10(9) IU/mL using cloned plasmids. The within-run coefficient of variation (CV) was 9.4%, 2.1%, and 1.1%, and the total CV was 11.8%, 3.6%, and 1.7% at a concentration of 1.92 log10 IU/mL, 3.88 log10 IU/mL, and 6.84 log10 IU/mL, respectively. No cross-reactivity or interference was detected. The ExiStation HBV diagnostic system showed satisfactory analytical sensitivity, excellent reproducibility, no cross-reactivity, no interference, and high agreement with the Cobas TaqMan and Abbott real-time PCR systems, and is therefore a useful tool for the detection and monitoring of HBV infection.
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http://dx.doi.org/10.1016/j.jviromet.2013.07.027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7119692PMC
November 2013

Differences in the frequency of 23S rRNA gene mutations in Mycoplasma pneumoniae between children and adults with community-acquired pneumonia: clinical impact of mutations conferring macrolide resistance.

Antimicrob Agents Chemother 2012 Dec 24;56(12):6393-6. Epub 2012 Sep 24.

Department of Laboratory Medicine, Inje University College of Medicine, Seoul, Republic of Korea.

We investigated the frequency and clinical significance of macrolide resistance in adult and pediatric patients with community-acquired pneumonia from a Mycoplasma pneumoniae infection. The frequency of the A2063G mutation in the 23S rRNA gene was significantly higher in children than in adults (61.3% [19/31] and 13.3% [8/60], respectively; P < 0.001). Patients with macrolide-resistant M. pneumoniae infections showed a longer duration of fever (P = 0.021) and required a longer duration of antibiotic treatment (P = 0.007).
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http://dx.doi.org/10.1128/AAC.01421-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3497172PMC
December 2012

Comparison of BD GeneOhm Cdiff and Seegene Seeplex ACE PCR assays using toxigenic Clostridium difficile culture for direct detection of tcdB from stool specimens.

J Clin Microbiol 2012 Nov 5;50(11):3765-7. Epub 2012 Sep 5.

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, South Korea.

We evaluated the performances of 2 PCR assays (BD GeneOhm and Seegene ACE) for direct detection of tcdB from stool specimens. The concordance rate between BD and Seegene was 96.3%. The sensitivities, specificities, positive predictive values (PPVs), and negative predictive values (NPVs) of BD and Seegene were 95.7%, 96.5%, 91.8%, and 98.2% and 90.0%, 97.1%, 92.6%, and 96.0%, respectively.
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http://dx.doi.org/10.1128/JCM.01440-12DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3486254PMC
November 2012

[Current status of external quality assessment of fecal occult blood test].

Korean J Lab Med 2010 Dec;30(6):726-33

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, Korea.

Background: Nationwide external quality assessment (EQA) of the fecal occult blood test (FOBT) in Korea was first introduced in 2007-2009. The EQA results were analyzed to assess the current status of FOBT and to plan the continuation of the EQA program.

Methods: The surveys included 40 hospitals in the preliminary survey conducted in 2007, 249 general hospitals in 2008, and 389 hospitals in 2009. In the surveys, the participating hospitals provided the results of the distributed materials and replies to the questionnaire on the FOBT test procedures and quality controls.

Results: In the surveys conducted between 2007 and 2009, a total of 650 institutes submitted 653 test system results; 3 institutes used 2 kinds of methods. All of the institutes used immunologic methods; 107 institutes (16.5%) used quantitative equipments and 546 institutes (84.0%) used qualitative kits. Most quantitative tests yielded consistent positive or negative results; however, their cut-off and measured values differed according to the equipments used. A low-level material tested in 2007 was negative in the quantitative methods but positive in some qualitative methods because of lower detection limits. The discordance rates among quantitative tests were 3.2% in 2007, 4.4% in 2008, and 0% in 2009 and the rates among qualitative tests were 13.8% in 2008 and 2.6% in 2009. Semi-solid EQA materials showed the ability to evaluate the overall test procedures with acceptable stability.

Conclusions: In the first Korean FOBT EQA, commercially available EQA materials were proven to be stable. Continuation of the EQA program and further education of laboratory personnel are needed to reduce inconsistency in results. Further, the test kit, procedures, and result reports must be standardized.
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http://dx.doi.org/10.3343/kjlm.2010.30.6.726DOI Listing
December 2010

[A case of hemophagocytic syndrome complicated by acute viral hepatitis A infection].

Korean J Hepatol 2010 Mar;16(1):79-82

Department of Internal Medicine, Inje University College of Medicine, Sanggye Paik Hospital, Seoul, Korea.

Hemophagocytic syndrome (HPS) is a rare but serious condition that is histopathologically characterized by activation of macrophage or histiocytes with hemophagocytosis in bone marrow and reticuloendothelial systems. Clinically it presents with high fever, hepatosplenomegaly, pancytopenia, liver dysfunction, and hyperferritinemia. Hepatitis A virus is a very rare cause of secondary HPS. We report a case of a 22-year-old woman infected by hepatitis A virus who was consequently complicated with HPS. She presented typical clinical features of acute hepatitis A, and showed clinical and biochemical improvements. However, HPS developed as a complication of acute hepatitis A and the patient died of intraperitoneal bleeding caused by hepatic decompensation and disseminated intravascular coagulation.
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http://dx.doi.org/10.3350/kjhep.2010.16.1.79DOI Listing
March 2010

[Recombinant chromosome 4 with partial 4p deletion and 4q duplication inherited from paternal pericentric inversion].

Korean J Lab Med 2010 Feb;30(1):89-92

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Pericentric inversion of chromosome 4 can give rise to 2 alternate recombinant (rec) chromosomesby duplication or deletion of 4p. The deletion of distal 4p manifests as Wolf-Hirschhorn syndrome (WHS). Here, we report the molecular cytogenetic findings and clinical manifestations observed in an infant with 46,XX,rec(4)dup(4q)inv(4)(p16q31.3)pat. The infant was delivered by Cesarean section at the 33rd week of gestation because pleural effusion and polyhydramnios were detected on ultrasonography. At birth, the infant showed no malformation or dysfunction, except for a preauricular skin tag. Array comparative genomic hybridization analysis of neonatal peripheral blood samples showed a gain of 38 Mb on 4q31.3-qter and a loss of 3 Mb on 4p16.3, and these results were consistent with WHS. At the last follow-up at 8 months of age (corrected age, 6 months), the infant had not achieved complete head control.
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http://dx.doi.org/10.3343/kjlm.2010.30.1.89DOI Listing
February 2010

Comparison of VIDAS CDAB and CDA immunoassay for the detection of Clostridium difficile in a tcdA- tcdB+ C. difficile prevalent area.

Anaerobe 2009 Dec 20;15(6):266-9. Epub 2009 Sep 20.

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, 139 707, Korea.

Enzyme immunoassays for TcdA and/or TcdB are widely used for diagnosis of C. difficile infection. This study compared the performance of the new VIDAS C. difficile Toxin A & B assay (CDAB) with that of the existing VIDAS C. difficile Toxin A II assay (CDA) in a tcdA(-)tcdB(+) prevalent area. A total of 555 fecal samples were cultured and tested using CDAB and CDA. C. difficile was isolated in 150 samples and the concordance rate was 81.8% (454/555) between CDAB and CDA. PCR assays for tcdA and/or tcdB were used as a confirmatory test on C. difficile strains recovered from culture positive cases (n=150) and on fecal specimens in culture negative/CDAB positive or equivocal cases (n=27). The number of tcdA(+)tcdB(+), tcdA(-)tcdB(+), and tcdA(-)tcdB(-) strains on culture positive isolates (n=150) were 75 (50.0%), 41 (27.3%), and 34 (22.7%), respectively. PCR assays for tcdB gene alone in stool specimens (n=27) showed positivity in five cases. The sensitivity of VIDAS CDAB was higher than that of VIDAS CDA (65.3% vs. 29.8%), by more than 2-fold. The specificity of CDAB was almost the same as CDA (93.8% vs. 94.5%). Toxigenic culture of C. difficile isolates in culture positive/VIDAS CDAB negative cases (n=62) additionally detected 22 VIDAS CDAB positive and 9 VIDAS CDAB equivocal cases. The VIDAS CDAB assay detects more tcdA(+)tcdB(+) strains (60% vs. 45.3%) and tcdA(-)tcdB(+) strains (70.7% vs. 0%) compared with VIDAS CDA.
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http://dx.doi.org/10.1016/j.anaerobe.2009.09.008DOI Listing
December 2009

[Meta-analysis for the pooled sensitivity and specificity of anti-human immunodeficiency virus Ab rapid tests].

Korean J Lab Med 2009 Aug;29(4):345-52

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Background: Many immunochromatography (ICA) kits for anti-human immunodeficiency virus type (HIV) antibody (Ab) have been introduced to improve the accessibility of HIV Ab tests. However, qualified evaluation reports for HIV rapid tests are not enough to validate their performances. Meta-analysis for the performances of the HIV Ab rapid tests was performed in this study.

Methods: PubMed database was searched with combination of search terms, 'human immunodeficiency virus', 'HIV Ab', 'rapid test', 'immunochromatography', 'performance', 'sensitivity', and 'specificity'. Criteria of inclusion were performance studies for HIV ICA kits with serum or EDTA whole blood. Methodological qualities were evaluated with standards for reporting of diagnostic accuracy studies (STARD) checklists by two investigators. Homogeneity among selected studies was evaluated and then pooled sensitivity and specificity were calculated. Positive and negative predictive values were simulated with presumed HIV prevalence in Korea.

Results: Twenty-three studies were selected from 12 high-qualified papers with STARD checklists. The performance of 23 studies were found to be heterogeneous (P<0.1) and random effect model was used. Pooled sensitivity was 99.71% (95% CI: 99.45-99.97%) and pooled specificity was 99.27% (95% CI: 98.83-99.70%). With HIV prevalence of 0.03%, positive and negative predictive values were presumed to be 3.936% and 99.999%, respectively.

Conclusions: This meta-analysis for HIV ICA rapid tests showed good performance. In consideration of low positive predictive values of HIV rapid tests, confirmation by enzyme immunoassay or Western blot is still needed. This study would be helpful in evaluating and establishing proper performance guideline for those kits not fully evaluated.
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http://dx.doi.org/10.3343/kjlm.2009.29.4.345DOI Listing
August 2009

[Influence of the pre-analytical specimen storage conditions on the fecal occult blood test results].

Korean J Lab Med 2009 Jun;29(3):262-7

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Nowon-Gu, Seoul, Korea.

Background: Korean national cancer screening program selected fecal occult blood test (FOBT) as a primary screening method of colorectal carcinoma in adult > or =50 yr old irrespective of symptom. Notice to pre-analytical errors is especially important for the FOBT because examinees collect and submit their specimens to laboratories by themselves. We examined the influences of the fecal storage temperatures, durations and with or without buffer on the FOBT results.

Methods: Thirty FOBT-positive specimens above 100 ng/mL were used for the study from July to August 2008. Quantitative FOBT was performed with OC-sensors II (Eiken Chemical Co., Japan). Each specimen was divided into 4 groups. Two groups in plastic buffer-free containers were kept either at 4 degrees C or room temperature (25-28 degrees C), respectively. Another two groups in buffer-tubes were also kept either at 4 degrees C or room temperature. Each group was repeatedly examined with same method every 24 hr up to 120 hr.

Results: Eleven specimens (36.7%) in buffer-free containers converted to negative results (below the 100 ng/mL) after 24 hr and 17 specimens (56.7%) did after 48 hr at room temperature. Ten specimens (33.3%) in buffer-free containers converted to negative after 48 hr at 4 degrees C. Specimens contained in buffer-tubes showed little change; 3 specimens (10.0%) at room temperature and no specimen at 4 degrees C showed negative conversions after 48 hr.

Conclusions: Buffer-tube minimizes false negative FOBT results during pre-analytical delay of specimen. The examinees using buffer-free containers need to be educated to hand in their specimens to laboratories as soon as possible.
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http://dx.doi.org/10.3343/kjlm.2009.29.3.262DOI Listing
June 2009

[Comparison of two enzyme immunoassay for detection of Clostridium difficile toxin A and toxin B].

Korean J Lab Med 2009 Apr;29(2):122-6

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Nowon-gu, Seoul, Korea.

Background: Enzyme immunoassay (EIA) capable of detecting both toxin A and toxin B is strongly recommended for the diagnosis of Clostridium difficile associated disease. Therefore, we evaluated two different EIAs for the detection of C. difficile toxin A/B.

Methods: For a total of 228 stool specimens we performed bacteriologic cultures for C. difficile and examined for toxin A and toxin B using enzyme linked fluorescent immunoassay (ELFA; VIDAS CDAB, Bio-Merieux sa, France) and ELISA (C.DIFFICILE TOX A/B II, TECHLAB, USA). We also performed PCR assays for toxin A and B genes in 117 C. difficile isolates that grew from the stool cultures and compared the results with those obtained with the two different EIAs.

Results: The concordance rate between ELFA and ELISA was 85.5% (195/228). Using the culture and PCR results as the standard, the sensitivity/specificity of the ELFA and ELISA were 65.0%/72.1% and 71.8%/70.3%, and for positive/negative predictive values were 78.4%/69.6% and 71.8%/70.3%, respectively (P value >0.05). No differences were observed between the results of ELFA and ELISA with toxin A(-) toxin B(+) strains of C. difficile.

Conclusions: The sensitivity of the ELISA was slightly higher than that of ELFA for toxin A and toxin B, but the specificity and positive predictive value of the ELFA were rather higher than those of the ELISA, although no statistical differences were observed. A bacteriologic culture and PCR assay for toxin genes are recommended in case the both EIAs are negative.
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http://dx.doi.org/10.3343/kjlm.2009.29.2.122DOI Listing
April 2009

[Co-circulation of two genotypes of hepatitis A virus from sporadic cases in northeastern area of Seoul, Korea].

Korean J Lab Med 2008 Oct;28(5):371-7

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Background: In previous studies, most hepatitis A virus (HAV) isolates had been genotype IA in Korea. Recently, a small number of different genotypes were reported with an upsurge of acute hepatitis by HAV. We investigated the distribution of HAV genotypes.

Methods: RNA was extracted from anti-HAV IgM positive sera which were collected from March 2007 to February 2008 at a tertiary care hospital in Northeastern Seoul, Korea. Nested reverse transcription (RT)-PCR and direct sequencing for VP1/P2A region of the HAV were performed.

Results: A total of 699 cases with suspected acute hepatitis were tested for anti-HAV IgM, and positive results were obtained in 56 sera (8.0%), which were collected 2 to 15 days (median, 7 days)after the onset of symptoms. Of the 56 seropositive samples, 52 (92.9%) were positive for HAV RNA, among which 28 isolates (53.8%) belonged to genotype IA and the remaining 24 (46.2%) belonged to genotype IIIA. Both IA and IIIA genotypes were isolated from 6-7 neighboring administrative districts throughout the year without geographic or seasonal restrictions.

Conclusions: Co-circulation of two distinct HAV genotypes (IA and IIIA) was observed from the northeastern Seoul for the year studied.
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http://dx.doi.org/10.3343/kjlm.2008.28.5.371DOI Listing
October 2008

Low frequency and variability of FLT3 mutations in Korean patients with acute myeloid leukemia.

J Korean Med Sci 2008 Oct;23(5):833-7

Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.

FLT3 mutations are common genetic changes, and are reported to have prognostic significance in acute myeloid leukemia (AML). The FLT3 internal tandem duplication (ITD) and the D835 activating mutation in the tyrosine kinase domain (TKD) were analyzed by polymerase chain reaction (PCR) in the genomic DNA of Korean patients with AML at diagnosis and during follow-up. There were 226 patients with AML enrolled between March 1996 and August 2005. The incidence of ITD and TKD at diagnosis was 13% (29/226) and 3% (6/226). When compared to Western and other Asian patients with AML, Korean patients had a lower frequency by about two-thirds of ITD and TKD. Among the non-M3 cases (N=203), the patients with an ITD had a significantly shorter event-free survival when compared with those without an ITD (p=0.0079). Among 54 relapsed patients, 9 patients had the FLT3 ITD at diagnosis. Six patients demonstrated a reappearance of the ITD and 3 patients remained negative at relapse. One patient, among 45 patients who relapsed, had a negative baseline ITD but acquired a de novo ITD at relapse. There were 101 samples from 93 patients in remission; they were all negative for an ITD. Among 34 patients who failed to achieve a remission, five patients had a persistent ITD and one patient had a de novo ITD. These results support the concept of resistance of FLT3 ITD leukemic clones to chemotherapy. Therefore, effective therapy with FLT3 targeting agents may improve the prognosis of non-M3 AML patients with the FLT3 mutation.
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http://dx.doi.org/10.3346/jkms.2008.23.5.833DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2580007PMC
October 2008

Detection of 12 respiratory viruses with two-set multiplex reverse transcriptase-PCR assay using a dual priming oligonucleotide system.

Korean J Lab Med 2007 Dec;27(6):420-7

Department of Laboratory Medicine, Sanggye Paik Hospital, School of Medicine, Inje University, Seoul, Korea.

Background: We intended to evaluate the diagnostic usefulness of a multiplex reverse transcriptase- PCR (mRT-PCR) assay kit under dual priming oligonucleotide system (DPO) for the childhood acute respiratory tract infections.

Methods: Two hundred nasopharyngeal aspirates were taken from children < or =5 yr old admitted due to acute respiratory infections in 2004. Direct fluorescent antibody (FA) assays were performed with fresh specimens; then, mRT-PCRs for the detection of 12 respiratory viruses (Seeplex RV detection kit, SeeGene, Seoul, Korea) were tested with frozen specimens.

Results: FA assays for five common respiratory viruses showed positive results in 66 patients (33.0%), while mRT-PCR detected causative viruses in 112 patients (56.0%), including 16 co-infected cases (8.0%). A total of 129 viruses were identified: respiratory syncytial virus A/B (38.0%/7.8%), influenza virus A/B (10.1%/5.4%), parainfluenza virus 1/2/3 (7.0%/3.1%/7.8%), coronavirus 229E or NL63 (6.2%), human metapneumovirus (4.7%), adenovirus (4.7%), rhinovirus (3.9%), and coronavirus OC43 (1.6%).

Conclusions: DPO-based mRT-PCR was found as a sensitive tool for the detection of the viruses that cause childhood respiratory infections. Clinical significances of the agents detected by mRTPCR need further evaluations.
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http://dx.doi.org/10.3343/kjlm.2007.27.6.420DOI Listing
December 2007

[Comparison of three assay systems for qualitative and quantitative results of hepatitis B surface antibody.].

Korean J Lab Med 2006 Dec;26(6):431-5

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Background: With a technical improvement of the assay system, automated immunoassay analyzers for hepatitis B surface antibody (anti-HBs) are widely used. However, some discrepancies between assays are still being reported. We compared the qualitative and quantitative results of three kinds of anti-HBs assays.

Methods: Serum samples were collected from 517 patients and anti-HBs were determined using AxSYM AUSAB, Bayer ADVIA Centaur, and Roche Elecsys assay systems.

Results: The concordance rates between the three assays were 95.1% (543/571). The concordance rates were 97.7% between Centaur and Elecsys, 96.3% between AxSYM and Centaur, and 95.6% between AxSYM and Elecsys. Their correlation coefficients for quantitative results were 0.97, 0.94, and 0.93 in the same order. Twenty-eight specimens showed discrepant results, and all of them had antibody values below 31.5 mIU/mL.

Conclusions: Three immunoassays for anti-HBs presented a high concordance and correlation; however, the results should be interpreted with caution, because there were still significant differences between assay methods, especially for a low-level of anti-HBs.
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http://dx.doi.org/10.3343/kjlm.2006.26.6.431DOI Listing
December 2006

[Comparison of Two Enzyme Immunoassays for Clostridium difficile Toxin A.].

Korean J Lab Med 2006 Dec;26(6):408-11

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University, Seoul, Korea.

Background: Clostridium difficile is one of the most important pathogens responsible for nosocomial diarrhea. The disease is mediated by two toxins, designated as A and B; therefore, identification of the toxins is important for diagnosis. However, culture or cytotoxin assay are not easily done because of tedious procedures. Instead, toxin A immunoassay is widely used. We evaluated two different enzyme immunoassays (EIA) for C. difficile toxin A and compared them with culture and PCR results.

Methods: A total of 65 stool specimens were examined for toxin A using enzyme linked fluorescent immunoassay (ELFA, VIDAS CD II, Bio-Merieux, France) and enzyme linked immunosolvent assay (ELISA, C.DIFFICILE TOX A II, TECHLAB, USA ) and were also cultured for C. difficile using cycloserine cefoxitine fructose agar. We amplified toxin A and B genes using primers NK9-NK 11 and NK104-NK105, respectively, in 23 C. difficile isolates.

Results: The concordance rate between ELFA and ELISA was 76.9%. The sensitivity and specificity of the ELFA and ELISA based on the culture and PCR results for toxin A gene were 84.6%/98.1% and 84.6%/67.3%. Positive and negative predictive values were 91%/96.2% in VIDAS and 78.0%/ 94.6% in TECHLAB. The positive rates of toxin B genes were 100%, 83.3% and 50% in toxin A positive, variant and negative strains, respectively.

Conclusions: The sensitivities of the ELFA and ELISA for toxin A were the same, but specificity and positive predictive value of the ELFA were higher than those of the ELISA. PCR or EIA method detecting both toxin A and toxin B is strongly recommended, because the variant strains (toxin A negative and toxin B positive) of C. difficile may be more prevalent than were anticipated in Korea.
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http://dx.doi.org/10.3343/kjlm.2006.26.6.408DOI Listing
December 2006

[Comparison of 3 automated immunoassays for hepatitis B surface antigen.].

Korean J Lab Med 2006 Aug;26(4):282-6

Department of Laboratory Medicine, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Korea.

Background: Hepatitis B surface antigen (HBsAg) is one of the most important serological markers used to diagnose hepatitis B virus (HBV) infection. Automated immunoassays have been developed, meeting the current clinical requirement of HBsAg assays over the years. This study was performed to determine the degree of agreements between 3 kinds of HBsAg assay systems.

Methods: Serum samples from 425 patients were assayed by the HBsAg assay systems of Elecsys (Roche Diagnostics, Germany), ADVIA Centaur (Bayer Diagnostics, USA), and AxSYM (Abbott Laboratories, USA).

Results: The concordance rates among the 3 assays were 100%. A total of 249 (58.6%) specimens were positive, and their index values showed a weak correlation between the 3 assays; nevertheless, positive specimens with low levels (<10) of index values in one system also presented low values in other systems, and all of them were confirmed by neutralization assays.

Conclusions: The 3 automated HBsAg assay systems presented a high level of concordance.
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http://dx.doi.org/10.3343/kjlm.2006.28.4.282DOI Listing
August 2006