Suggestions for Specialization and Enhancing Capacity in National Blood Services / 대한수혈학회지

Blood is an essential medical resource for treating diseases and trauma of people, but a limited biological resource for which no artificial production is possible. Therefore, systematic and rational management of its supply and use must be carried out under the national responsibility. On the other hand, the low birthrate and aging population have raised the problem of blood shortages in Korea. To help solve this problem, this study examined proposals for the development of a blood management system in Korea. In addition, the works of blood management bodies were analyzed based on the operation subjects and types of blood projects in the United States, the United Kingdom, France, Germany, the Netherlands, Canada, Australia, Singapore, and Japan. Based on these data, this paper proposes a new organization that can best enhance the specialization of national blood services and strengthen its capacity under the current blood supply system in Korea.

Long-Term Stability of HBV, HCV, and HIV-1 National Reference Standards for in vitro Diagnostic Medical Devices Intended to Be Used for the Nucleic Acid Amplification Test / 대한수혈학회지

BACKGROUND: National reference standards are essential to the quality assessment and regulatory approval of in vitro diagnostic medical devices. However, the long-term stability of national reference standards has not been comprehensively secured. This study was performed to assessment on the long-term stability of the hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus-1 (HIV-1) national reference standards intended to be used for the nucleic acid amplification test (NAT). METHODS: The viral loads of the MFDS (Korea Ministry of Food and Drug Safety) working standard and recombinant DNA for HBV, HCV, and HIV-1 were measured before and after storage at −70℃ for up to 72 months using Cobas Ampliprep/Cobas Taqman assays (Roche Molecular System, Inc., Branchburg, USA) at defined time points. RESULTS: The viral loads of national reference standards for in vitro diagnostic medical devices of HBV, HCV, and HIV-1 stored at −70℃ for up to 72 months did not differ significantly from the baseline viral load. The changes in viral load of national reference standards of HBV, HCV, and HIV-1 tested after storage at −70℃ for up to 72 months ranged from −0.36 to 0.16 log10 IU/mL and did not exceed 0.5 log10, which is the estimated intra-assay variation of molecular tests. CONCLUSION: The HBV, HCV, and HIV-1 national reference standards for in vitro diagnostic medical devices intended to be used for the NAT were relatively stable after long-term storage at −70℃ for up to 72 months, regardless of the initial titer.

Proposal of Modified HIL-indices for Determining Hemolysis, Icterus and Lipemia Interference on the Beckman Coulter AU5800 Automated Platform

BACKGROUND: The amount of interference due to hemolysis, bilirubin, and lipemia can be measured on the AU5800 autoanalyzer (Beckman Coulter, USA) by spectrophotometry. This is reported as semi-quantitative indices, specifically H-index, I-index, and L-index, respectively. In this study, we evaluated the impact of interference using chemistry assays and established the concentration of interfering substances and HIL-index above which analytically significant interference exists, according to CLSI guidelines C56-A and EP7-A2. METHODS: Pooled sera including different concentrations of analytes were prepared and mixed with hemoglobin, bilirubin, or Intralipid. These samples were then tested for 35 clinical chemistry analytes by AU5800 and the bias based on interferent concentrations was computed. The interferent concentration above which significant interference exists was calculated from the 50% within-subject biological variation (desirable analytic goal), and the corresponding index was assigned. RESULTS: Among 35 items evaluated, interference was detected for 12 analytes by hemoglobin, 7 analytes by bilirubin, and 12 analytes by Intralipid. We proposed HIL-index₁ and HIL-index₂ for each analyte according to 2 different medical decision levels. HIL-index₁ and HIL-index₂ were considered more reasonable criteria than the HIL-index from the manufacturer's technical document (HIL-index(TD)). This is because HIL-index(TD) was empirically set to 5% or 10%, and had a wide tolerance range, which was not sufficient to reflect the presence of interference, compared to HIL-index₁ and HIL-index₂. CONCLUSIONS: We have demonstrated hemoglobin, bilirubin, and Intralipid interferences according to CLSI guidelines using the desirable analytic goal. Our results provide applicable information for Beckman Coulter automated chemistry analyzers.

Annual Report on the External Quality Assessment Scheme of Viral Markers and Serological Tests for Syphilis in Korea (2015)

As the Immunoserology Subcommittee of the Korean Association of External Quality Assessment, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2015. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,071 and 1,074 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability using multiple methods between the day of their manufacture and three days after dispatching. The number of participating laboratories was 1,055 (98.5%) and 1,055 (98.2%) in the first and second trial, respectively. The most commonly tested items were hepatitis B surface antigen, followed by the antibodies to hepatitis B surface antigen, antihuman immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which were found to generate few false positive results. In contrast, false negative results were frequently found when the immunochromatographic assay (ICA) was used; the use of ICA for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, tests recently introduced for the measurement of nontreponemal and treponemal antibodies, is also increasing.

Evaluation of the VIDAS Anti-HCV Assay for Detection of Hepatitis C Virus Infection

BACKGROUND: Anti-hepatitis C virus antibody (anti-HCV) assays are recommended for screening HCV-infected persons. The VIDAS Anti-HCV Assay (bioMérieux, France), based on the enzyme-linked fluorescence test principle, was recently introduced in Korea. We evaluated the clinical performance of the VIDAS assay. METHODS: One hundred HCV-positive and 1,002 HCV-negative blood samples confirmed by Architect anti-HCV (Abbott Laboratories, USA) and COBAS TaqMan HCV real-time PCR (Roche Diagnostics, USA) or the Procleix Ultrio Plus Assay (Gen-Probe Incorporated, USA) were obtained from the Human Serum Bank (HSB) and tested by VIDAS. In case of discrepant results, we conducted a recombinant immunoblot assay (RIBA). RESULTS: The agreement rates for known HCV-positive and HCV-negative samples between the VIDAS assay and the HSB testing were 100% (95% confidence interval [CI]: 96.4-100%) and 99.5% (95% CI: 98.8-99.8%), respectively. One of the five discrepant samples was positive for Core 2+ and NS3-2 2+ reactivity, two samples were negative, and the other two were indeterminate regarding NS4 2+ reactivity in RIBA. We observed a significant but weak positive correlation between the titers of VIDAS and Architect assays (r=0.315, P<0.001). CONCLUSIONS: The VIDAS anti-HCV assay, developed on the VIDAS automated immunoassay platform based on the ready-to-use, single-sample test concept may be useful in small-to-medium-sized laboratories. It showed good agreement with Architect anti-HCV and COBAS PCR assays and is therefore useful for detection of HCV infection. Weakly test-positive (ambiguous) samples require additional testing by another anti-HCV, RIBA, or HCV RNA assay.

Results of Proficiency Tests for HBsAg and Anti-HCV as the Blood Donor Screening Testing (2012~2015) / 대한수혈학회지

BACKGROUND: Donor screening test is one of the most important processes for blood safety management. Korea Center for Disease Control and Prevention (KCDC) has been conducting an annual proficiency test program that includes the distribution of specially manufactured panels for hepatitis B surface antigen (HBsAg) and antibody to hepatitis C virus (anti-HCV) to blood centers. Here, KCDC reports the results of these proficiency tests for HBsAg and anti-HCV blood donor screening for all licensed blood centers in Korea between 2012 and 2015. METHODS: Panels for the proficiency tests were manufactured and distributed to blood centers by Chung-Ang University Hospital, which has been participating in the Korea Blood Safety Commission. Well-proven reactive sera and healthy donor's sera acquired from the Human Serum Bank in Chung-Ang University were used to make the panels. To identify the S/CO ratio of the panel, three medical institutes triple-checked the results of each panel. RESULTS: Most blood centers reported correct answers for the proficiency test with six panels. The average percentages (year) of correct answers were as follows: 98.7% (2012), 98.5% (2013), 99.1% (2014) and 99.6% (2015) for the HBsAg proficiency tests; and 97.7% (2012), 99.5% (2013), 99.1% (2014), and 99.8% (2015) for the anti-HCV proficiency tests. CONCLUSION: To improve the blood center's ability for donor screening tests, KCDC will continue the proficiency test program by managing specialized panels for HBsAg and Anti-HCV tests. Furthermore, we will investigate the level of satisfaction to improve the quality of the program.

Performance Evaluation of BAROZEN H, a Networking Blood Glucose Monitoring System for Medical Institutions

BACKGROUND: We evaluated the analytical performance of Barozen H (i-SENS Inc., Korea), a new glucometer equipped with networking function for medical institutions, according to the ISO 15197:2003 and ISO/DIS 15197:2011 guidelines. METHODS: We measured the precision of 10 Barozen H glucometers, in terms of repeatability and intermediate precision, and determined their accuracy relative to that of automatic chemistry analyzer AU5421 (Beckman Coulter, USA). Three other glucometers-Precision PCx (Abbott, USA), Glucocard Sigma (Arkray, Japan), and SureStep Flexx (Johnson & Johnson, USA) were also evaluated, and their accuracies and hematocrit interferences were compared. RESULTS: The standard deviation and coefficient of variation of Barozen H for repeatability and intermediate precision were 0.11-0.15 mmol/L and 2.3-3.6%, respectively. With respect to accuracy, in accordance with ISO 15197:2003 criteria, Barozen H yielded 98.0% of results within +/-0.83 mmol/L or +/-20%. Further, per the ISO/DIS 15197:2011 criteria, 95.2% of results were within +/-0.83 mmol/L or +/-15%; Barozen H was the only glucometer satisfying the more stringent ISO/DIS 15197:2011 criteria. Error grid analysis showed that all results from Barozen H were in zone A, indicating its excellent clinical accuracy. Hematocrit, ranging from 20% to 60% did not cause any significant interference. CONCLUSIONS: Barozen H showed excellent analytical performance, and it was the most clinically accurate glucometer tested. It can be expected to provide reliable results satisfying ISO/DIS 15197:2011 as well as ISO 15197:2003 criteria.

A Comparison of the Performance of Soyagreentec Ampulab EDTA and Sodium Citrate Tubes with That of BD Vacutainer Tubes

BACKGROUND: Because blood collection tube can affect the results of various laboratory tests, it is necessary before using a newly developed product to verify its performance stringently and objectively. We compared the performance of Ampulab EDTA and sodium citrate tubes (Soyagreentec, Korea) with that of Vacutainer tubes (BD, USA) in accordance with international guidelines. METHODS: This study was performed as a multicenter study of Chung-Ang University Hospital and Seoul National University Hospital to evaluate the performance of two different instrument platforms. We performed the precision test according to CLSI GP34-A, the accuracy test according to CLSI EP09-A2-IR, and the vacuum test according to CLSI H1-A5 as well as stability, and aseptic condition tests. We evaluated 3 lots of Ampulab tubes for their precision, accuracy, vacuum, and aseptic condition. RESULTS: In precision test, the total precision levels of Ampulab tubes in most measurands were desirable or allowable. The results of mean corpuscular hemoglobin concentration, platelet distribution width, basophil, and reticulocyte counts for Ampulab tubes showed imprecision beyond allowable limits, but were similar to those of Vacutainer tubes. In the accuracy test, the bias in most measurands, except for the mean platelet volume, was within allowable limits. In the stability test, Ampulab showed similar performance to Vacutainer. In tests of the vacuum and aseptic conditions, Ampulab fulfilled both requirements. CONCLUSIONS: The performance of Ampulab EDTA and sodium citrate tubes was equivalent to that of Vacutainer tubes.

Performance Evaluation of BAROZEN H, a Networking Blood Glucose Monitoring System for Medical Institutions

BACKGROUND: We evaluated the analytical performance of Barozen H (i-SENS Inc., Korea), a new glucometer equipped with networking function for medical institutions, according to the ISO 15197:2003 and ISO/DIS 15197:2011 guidelines. METHODS: We measured the precision of 10 Barozen H glucometers, in terms of repeatability and intermediate precision, and determined their accuracy relative to that of automatic chemistry analyzer AU5421 (Beckman Coulter, USA). Three other glucometers-Precision PCx (Abbott, USA), Glucocard Sigma (Arkray, Japan), and SureStep Flexx (Johnson & Johnson, USA) were also evaluated, and their accuracies and hematocrit interferences were compared. RESULTS: The standard deviation and coefficient of variation of Barozen H for repeatability and intermediate precision were 0.11-0.15 mmol/L and 2.3-3.6%, respectively. With respect to accuracy, in accordance with ISO 15197:2003 criteria, Barozen H yielded 98.0% of results within +/-0.83 mmol/L or +/-20%. Further, per the ISO/DIS 15197:2011 criteria, 95.2% of results were within +/-0.83 mmol/L or +/-15%; Barozen H was the only glucometer satisfying the more stringent ISO/DIS 15197:2011 criteria. Error grid analysis showed that all results from Barozen H were in zone A, indicating its excellent clinical accuracy. Hematocrit, ranging from 20% to 60% did not cause any significant interference. CONCLUSIONS: Barozen H showed excellent analytical performance, and it was the most clinically accurate glucometer tested. It can be expected to provide reliable results satisfying ISO/DIS 15197:2011 as well as ISO 15197:2003 criteria.

A Comparison of the Performance of Soyagreentec Ampulab EDTA and Sodium Citrate Tubes with That of BD Vacutainer Tubes

BACKGROUND: Because blood collection tube can affect the results of various laboratory tests, it is necessary before using a newly developed product to verify its performance stringently and objectively. We compared the performance of Ampulab EDTA and sodium citrate tubes (Soyagreentec, Korea) with that of Vacutainer tubes (BD, USA) in accordance with international guidelines. METHODS: This study was performed as a multicenter study of Chung-Ang University Hospital and Seoul National University Hospital to evaluate the performance of two different instrument platforms. We performed the precision test according to CLSI GP34-A, the accuracy test according to CLSI EP09-A2-IR, and the vacuum test according to CLSI H1-A5 as well as stability, and aseptic condition tests. We evaluated 3 lots of Ampulab tubes for their precision, accuracy, vacuum, and aseptic condition. RESULTS: In precision test, the total precision levels of Ampulab tubes in most measurands were desirable or allowable. The results of mean corpuscular hemoglobin concentration, platelet distribution width, basophil, and reticulocyte counts for Ampulab tubes showed imprecision beyond allowable limits, but were similar to those of Vacutainer tubes. In the accuracy test, the bias in most measurands, except for the mean platelet volume, was within allowable limits. In the stability test, Ampulab showed similar performance to Vacutainer. In tests of the vacuum and aseptic conditions, Ampulab fulfilled both requirements. CONCLUSIONS: The performance of Ampulab EDTA and sodium citrate tubes was equivalent to that of Vacutainer tubes.

Annual Report on the External Quality Assessment Scheme of Viral Markers and Serological Tests for Syphilis in Korea (2014)

As Immunoserology Subcommittee of the Korean Association of External Quality Assessment Service, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2014. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,060 and 1,064 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability by using more than three other methods between the day of their manufacture and 3 days after despatching. The numbers of participating laboratories were 1,053 (99.3%) and 1,046 (99.3%) in the first and second trials, respectively. The most commonly tested items were hepatitis B surface antigen, followed by antibody to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which generated few false positive results. In contrast, false negative results were frequently found through the immunochromatography assay, the use of which for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, which are new tests recently introduced for the measurement of non-treponemal and treponemal antibodies, is also increasing.

Annual Report on External Quality Assessment of Viral Markers and Serological Tests for Syphilis in Korea (2013) / 임상검사와정도관리

We performed two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) organised by the Immunoserology Subcommittee of the Korean Association of Quality Assurance for Clinical Laboratories in 2013. In each trial, we delivered 3 kinds of pooled sera specimens to 1,021 institutions for external proficiency testing. Pooled sera were checked for their homogeneity and stability by using more than 3 other methods between the day of their manufacture and 3 days after despatching. The numbers of participating laboratories were 1,019 (99.8%) and 1,020 (99.8%) for the first and second trials, respectively. The most commonly tested items were hepatitis B surface antigen followed by antibody to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which generated a few false positive results. In contrast, false negative results were frequently found through the immunochromatography assay, the use of which for detecting viral markers has been steadily increasing in recent years. The new tests, turbidoimmunoassay and CLIA, have recently been introduced for the measurement of non-treponemal and treponemal antibodies, and their use is also increasing.

Verification of Comparability among Quantitative Results Obtained Using Multiple Instruments within a Health Care System

BACKGROUND: The comparability of results obtained for the same analyte using more than 1 instrument should be evaluated periodically. We used a standardized guideline (C54-A) proposed by the Clinical and Laboratory Standards Institute in 2008 to verify comparability of patient results between 2 automated biochemical analyzers used within 1 healthcare system. METHODS: Comparability between 2 automated biochemical analyzers [OLYMPUS AU5421 (Beckman-Coulter, USA)] were evaluated using patient blood samples. The test parameters were albumin, alkaline phosphatase, alanine transaminase, aspartate aminotransferase, blood urea nitrogen, calcium, cholesterol, creatinine, direct bilirubin, gamma-glutamyl transpeptidase, glucose, ionized phosphorus, lactate dehydrogenase, protein, total bilirubin, and uric acid. RESULTS: Quality control data for 6 months were used to calculate the desired concentration. Biological variation was used to establish critical differences and determine the number of replicates. The calculated ranges of all test parameters were less than their critical differences, so comparability between the 2 instruments was considered acceptable. CONCLUSIONS: The Clinical and Laboratory Standards Institute C54-A guideline is useful for the verification of comparability of results obtained with 2 instruments within 1 healthcare system.

Establishment and Multicenter Evaluation of a National Reference Panel for Syphilis Antibodies in Korea

BACKGROUND: Establishment of a national reference panel for syphilis antibodies is necessary to evaluate the performance of in-vitro diagnostic tests for syphilis and to verify test quality. This study aimed to establish a national reference panel for syphilis antibodies, to assess the suitability of a panel for non-treponemal and treponemal testing, and to assess the reactivity of the various tests currently in use. METHODS: Treponemal pallidum particle agglutination (TPPA)-positive and -negative fresh frozen plasma samples were obtained. After the fresh frozen plasma was converted to serum by defibrination, the samples were pooled. Two candidate reference standards containing no syphilis antibodies and 10 candidate reference standards containing syphilis antibodies were prepared on the basis of reactivity in the TPPA assay. Candidate reference standards were tested by three laboratories using five non-treponemal tests and four treponemal tests. RESULTS: All three laboratories reported positive non-treponemal test results for the mixed-titer performance panel (MP)/6-MP/12. MP/1, MP/2, and MP/3 were negative for non-treponemal tests. MP/4 and MP/5 were reported either as positive or negative according to the laboratories. All laboratories reported positive TPPA results for MP/3-MP/12 and negative results for MP/1 and MP/2. No significant difference was detected among the treponemal testing results in three laboratories. CONCLUSIONS: We established 12 candidate national reference standards containing various concentrations of syphilis antibodies. A collaborative study using nine tests demonstrated that 12 candidate national reference standards presented consistent results, except a few assays with low sensitivity, and thus could be used as a national reference panel for syphilis antibody testing.

Performance Evaluation of the OraQuick Hepatitis C Virus Rapid Antibody Test

BACKGROUND: A reliable rapid assay for hepatitis C virus (HCV) may be helpful in various clinical settings. We evaluated the performance of the OraQuick HCV Rapid Antibody Test (OraSure Technologies Inc., Bethlehem, PA, USA). METHODS: Clinical sensitivity and specificity were evaluated with oral fluids and sera from 137 patients diagnosed with hepatitis C and 300 healthy blood donors in a multi-center collaborative study. The stored sera of 200 proven HCV-infected patients and 200 healthy subjects were also evaluated. Analytical sensitivity was estimated with 4 commercial seroconversion panels and 7 Korean reference panels. The performance of 4 laboratory-based tests (3 chemiluminescence assays and 1 enzyme immunoassay) and 4 rapid test kits was compared. We also assessed the interference due to bilirubin, hemoglobin, lipid, rheumatoid factor, multipara, and several viral infections. RESULTS: The clinical sensitivity and specificity of the OraQuick HCV test using oral fluid were 97.8% (95% confidence interval [CI], 93.2-99.4%) and 100% (95% CI, 98.4-100%), respectively. The clinical sensitivity using serum samples was 100%. Using the 4 seroconversion panels, the OraQuick HCV test showed results comparable to those of the laboratory-based assays; its analytical sensitivity was higher than that of the other rapid test kits. There was no cross-reactivity with common interfering factors. CONCLUSIONS: The clinical performance of the OraQuick HCV Test is comparable to that of laboratory-based tests with both serum and oral fluid. This supports the supplementary use of rapid HCV testing using oral fluid in various medical and non-medical settings.

Performance Evaluation of the OraQuick Hepatitis C Virus Rapid Antibody Test

BACKGROUND: A reliable rapid assay for hepatitis C virus (HCV) may be helpful in various clinical settings. We evaluated the performance of the OraQuick HCV Rapid Antibody Test (OraSure Technologies Inc., Bethlehem, PA, USA). METHODS: Clinical sensitivity and specificity were evaluated with oral fluids and sera from 137 patients diagnosed with hepatitis C and 300 healthy blood donors in a multi-center collaborative study. The stored sera of 200 proven HCV-infected patients and 200 healthy subjects were also evaluated. Analytical sensitivity was estimated with 4 commercial seroconversion panels and 7 Korean reference panels. The performance of 4 laboratory-based tests (3 chemiluminescence assays and 1 enzyme immunoassay) and 4 rapid test kits was compared. We also assessed the interference due to bilirubin, hemoglobin, lipid, rheumatoid factor, multipara, and several viral infections. RESULTS: The clinical sensitivity and specificity of the OraQuick HCV test using oral fluid were 97.8% (95% confidence interval [CI], 93.2-99.4%) and 100% (95% CI, 98.4-100%), respectively. The clinical sensitivity using serum samples was 100%. Using the 4 seroconversion panels, the OraQuick HCV test showed results comparable to those of the laboratory-based assays; its analytical sensitivity was higher than that of the other rapid test kits. There was no cross-reactivity with common interfering factors. CONCLUSIONS: The clinical performance of the OraQuick HCV Test is comparable to that of laboratory-based tests with both serum and oral fluid. This supports the supplementary use of rapid HCV testing using oral fluid in various medical and non-medical settings.

Performance Evaluation of Immunoassay Detection of HBsAg Mutants and Their Clinical Significance in the High Risk Groups

BACKGROUND: False negative results have been reported in the immunodetection of hepatitis B virus (HBV) because of the existence of the various mutants of the virus, causing most suppliers to try to develop superior reagents by using highly sensitive and specific monoclonal or polyclonal antibodies. In this study, we evaluated the effectiveness of 3 newly developed reagents by major manufacturers by adopting automated methods with increased sensitivity and specificity in the detection and discrimination of native and recombinant mutant antigens. METHODS: We analyzed samples confirmed positive for hepatitis B surface antigen (HBsAg), high-risk samples from chronic hepatitis patients treated with antiviral agents, and samples from patients who had undergone liver transplantation and were treated with high-dose hepatitis B immunoglobulin (HBIG) by using reagents and systems newly developed by Abbott Laboratories (USA), Roche Diagnostics (Germany), and Siemens Healthcare Diagnostics (USA). Recombinant sample panels from these manufacturers with low and high concentrations were also analyzed for comparing the 3 reagents. RESULTS: There were no discrepant results among the various selected patient groups; however, for the recombinant mutant panels, all of the 3 reagents showed highly positive detection rates for their corresponding mutant panels, but showed relatively discrepant mutant detection rates when cross-tested with the other mutant panels. Detection rates of the HBsAg mutant panels were higher at a higher concentration of the mutant samples, but were lower for the same mutant receptor sites at a lower concentration. CONCLUSIONS: The 3 major detection methods seem to recognize the major native mutants commonly encountered in clinical practice. However, in the case of recombinant mutants, we believe that our data are not to be interpreted as a reference standard for any reagent, because the results can only be validated for the reagents' corresponding mutant panels; such results tend to be mutually exclusive, and the enough concentration of mutants was required to be adjusted for a comparative analysis.

Performance Evaluation of 3 Kinds of HBsAg Qualitative Assays and 2 Kinds of Quantitative Assays

BACKGROUND: Currently used techniques for quantitation of HBsAg often yield discordant results; therefore, development of quantitation techniques that can detect HBsAg with high accuracy has become very important. Recent advances have led to the development of several HBsAg detection systems. Here, we evaluated the performance of 3 newly developed detection systems, which can detect HBsAg both qualitatively and quantitavely, and determined the concordance among their results. METHODS: Four hundred and thirty two samples assigned to 4 groups-patient group, dilution group, weakly reactive group, and linearity group- were subjected to qualitative and quantitative detection of HBsAg by using the 3 systems developed by 3 major manufacturers; Abbott Architect, Roche E170 and Siemens Centaur XP. RESULTS: The results for the qualitative analyses were closely concordant among the three systems (98.3%) for all 432 samples. In 123 samples that were determined as HBsAg-negative, E170 (76%) distributed frequently at the upper half level (0.5-1.0) of negative reference range, compared with Architect (11%) and Centaur XP (22%). In particular, in 65 samples that were diluted from the strongly positive samples to obtain weakly positive samples, the average index values obtained using Architect (3.6 S/CO), E170 (4.2 COI) and Centaur XP (11.4 index value) differed significantly (P<0.0001). In the antiviral treatment group and the post-liver transplantation group, no inconsistency was observed among the results of the qualitative and quantitative assays. In the 18-fold serially diluted samples, no linearity was observed. CONCLUSIONS: Because of the possibility of false-positive detection in the HBsAg-negative samples, regular management of equipment and appropriate selection of reagents are very important. In weakly positive samples, quantitative assay has not to be replaced for qualitative assay. Therefore, the qualitative assays should be used for screening the samples, whereas the quantitative assays should be used for monitoring the Hepatitis B virus (HBV) load in the samples determined as HBsAg-positive. The qualitative index value should not be interpreted as a quantitative measure of HBV load.

A Case of Isolated Light Chain Deposition Disease in the Duodenum

Light chain deposition disease (LCDD) is a rare disorder associated with a clonal proliferation of plasma cells, which synthesize abnormal monoclonal immunoglobulin light chains. LCDD is characterized by systemic deposition of light chains in various organs, with the kidneys being most commonly affected. There have been few reports of isolated LCDD. We report a rare case of LCDD limited to a duodenal polyp. A 63-yr-old man visited our hospital for health screening without symptoms in 2009. On gastrofiberscopy, a duodenal polyp was observed. The biopsy showed diffuse infiltration by atypical plasma cells, which were positive for kappa-type light chains by immunohistochemistry. While the patient refused further management, we could find no evidence of recurrence until 2 yr after the initial diagnosis. It has been reported that isolated LCDD has relatively good prognosis compared to systemic LCDD. However, treatment for this disease has not been established yet.

Report on External Proficiency Testing for Blood Grouping Tests in Blood Centers (2011) / 대한수혈학회지

BACKGROUND: To ensure safety of blood transfusion, accuracy in performance of blood grouping tests (BGT) is essential. External proficiency testing (PT) for BGT has not been conducted in Korea. The first PT for BGT in domestic blood centers was conducted in order to evaluate the domestic status of accuracy of BGT in blood centers and to aid in improving the quality of blood centers. METHODS: Whole blood survey specimens consisting of three panels for ABO grouping and two panels for Rh typing were sent to 81 blood centers. Evaluation criteria for BGT were as follows: 'Good' for answers with 100% referee consensus, 'Acceptable' for correct answers other than those of the referee, and 'Unacceptable' for answers other than those of 'Good+acceptable' as correct answers. RESULTS: Rates of correct answers on three panels for ABO grouping were all 100%; however, that of cell typing for the panel with BW was 61.7%, and 31 blood centers incorrectly reported normal 'B' type as an answer. The rate of correct answers for the Rh negative panel was 100%; however, that for the weak D panel was 84%, and 13 blood centers incorrectly reported Rh negative type as an answer. CONCLUSION: Findings from this study demonstrated that some hospital blood centers were not able to correctly detect blood groups with weak antigens. Therefore, to improve the quality of blood centers, intensive education for blood center staff and continued PT for BGT should be required.