BACKGROUND: The third generation anti-hepatitis C virus (HCV) enzyme immunoassay (EIA) is now in use for screening HCV infection. The aim of this study was to pool the data on the sensitivity and specificity of third generation anti-HCV EIA tests after evaluating the quality of the studies using Standards for Reporting of Diagnostic Accuracy studies (STARD) checklist. METHODS: We searched MEDLINE and PubMed databases using keywords about the accuracy of diagnostic tests for HCV infections. Methodological quality was assessed by two persons with a modified STARD checklist. A heterogeneity test was performed, and in case heterogeneity was present, a sub-group analysis was done. Fixed-effects model was used to obtain pool sensitivity and specificity with 95% confidence intervals (CI). RESULTS: A total of 41 studies from 16 papers were selected. The quality score ranged from 6 to 13 (median 10.5); Inter-observer agreement was 93.62% (k=0.69); and 41 studies revealed heterogeneity. We performed a sub-group analysis with only 28 studies from 13 papers that were evaluated to be of high quality. A subgroup using polymerase chain reaction as the reference test revealed homogeneity and was calculated the pooled sensitivity and specificity of 99.92% (CI 99.77-100.07%) and 99.66% (CI 99.45-99.86%) respectively. Studies on test kits with an increased reactivity to the core region also showed homogeneity in sensitivity and the pooled sensitivity was 99.78% (CI 99.53-100.03%). CONCLUSIONS: For the first time in Korea, the diagnostic accuracy of test kits was evaluated by meta-analysis using STARD checklist. The methodology shown in this study should help extending laboratory medicine to an evidence-based medicine.
Checklist* ; Diagnostic Tests, Routine* ; Evidence-Based Medicine ; Humans ; Immunoenzyme Techniques ; Korea ; Mass Screening ; Polymerase Chain Reaction ; Population Characteristics ; Sensitivity and Specificity*

BACKGROUND: Many studies evaluating the performance of in vitro diagnostic kits have been criticized for the lack of reliability. To attain reliability those evaluation studies should be preceded by sample size calculation ensuring statistical power. This study was intended to develop a web-based system to estimate the sample size, which was often neglected because it would require expert knowledge in statistics. METHODS: For sample size calculation, we extracted essential parameters from the performance studies on the 3rd generation anti-hepatitis C virus (HCV) kits reported in the literature. We developed a system with PHP web-script language and MySQL. The statistical models used in this system were as follows; one sample without power consideration (model 1), one sample with power consideration (model 2), and two samples with power consideration (model 3). RESULTS: Among the articles published between 1989 and 2005, 13 articles that evaluated the performance of anti-HCV kits were identified by searching with Medical Subject Headings (MeSH). The diagnostic sensitivity was 83-100% with a median of 145 samples (range; 12-1,091) and the specificity was 97-100% with a median of 1,025 samples (range; 33-4,381). The estimated sample size would be 280 in the model 1, 817 in the model 2, and 1,510 in the model 3, when we set 2% prevalence of HCV infection, 95% sensitivity of a conventional kit, 97% sensitivity of a new kit , 95% significance level (two-sided test), 2% allowable error, and 80% power. CONCLUSIONS: Our study indicates that an insufficient sample size is still a problem in performance evaluation. Our system should be helpful in increasing the reliability of performance evaluation by providing an appropriate sample size.
Medical Subject Headings ; Models, Statistical ; Prevalence ; Sample Size* ; Sensitivity and Specificity

BACKGROUND: The bcr-abl gene rearrangement is a very important genetic marker in at least 95% of cases of chronic myeloid leukemia (CML). The technique that allows the detection of bcr-abl gene rearrangement seem to be the testing for the diagnoses and the detection of minimal residual disease (MRD) and may help in monitoring patients. Recent introduction of real-time quantitative PCR should eventually allow actual quantification of the target gene during amplification. In the present study, we investigated bcr-abl chimeric mRNA quantification in CML after bone marrow transplantation (BMT) by real-time RT-PCR and its clinical applicability to the decision of therapeutic intervention. METHODS: The subjects were a consecutive series of 9 CML patients with serial quantification of bcr-abl chimeric mRNA by real-time RT-PCR in peripheral blood or bone marrow aspirates. The sensitivity of real-time RT-PCR was compared to conventional RT-PCR and then the correlation with FISH results was analyzed. RESULTS: Seventeen bone marrow samples and 40 peripheral bloods were obtained from patients. The sensitivity of real-time RT-PCR was 10(-6) and positive signals were detected in negative cases by conventional RT-PCR. A significant correlation between the bcr-abl/G6PDH ratio by real-time RT-PCR and the proportion of positive cells for bcr-abl gene rearrangement by FISH was obtained (r=0.64). In the serial blood and bone marrow specimens, we found a progressive decrease in the bcr-abl/G6PDH ratio in all the patients. CONCLUSIONS: Our findings indicated that quantitative analysis of bcr-abl chimeric mRNA by real-time RT-PCR might be a useful tool for the monitoring of minimal residual disease in bcr-abl positive leukemic patients.
Bone Marrow ; Bone Marrow Transplantation* ; Diagnosis ; Gene Rearrangement ; Genetic Markers ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive* ; Neoplasm, Residual ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction* ; RNA, Messenger

BACKGROUND: Additional tests ordered by doctors after checking abnormal routine test results for inpatients are usually delayed for one day or more, which in turn delays diagnostic and therapeutic procedures and prolongs length of stay (LOS) for the patients. We at Department of Laboratory Medicine, Asan Medical Center (AMC), established a "secondary order system for laboratory tests without additional blood sampling" to improve the conventional reflexive tests. METHODS: Oracle 8.0 (Oracle Co., Belmont, CA, USA) was used for data base software and Powerbuilder (Powersoft, Burlington, UK) for client development tool. Specimens subjected to "reflexive tests by doctors without additional blood sampling" were SST tubes for routine chemistry and EDTA for routine hematology requested in the morning of additional requests of the laboratory tests. RESULTS: Programs of registration and request for "reflexive tests by doctors without additional blood sampling" and bar code printing were developed for clinicians to check the routine test results and to order additional tests, if necessary, and for laboratory to perform the requested tests using the same samples used for routine chemistry and hematology tests in the morning. Additionally requested tests were done by finding the SST and EDTA samples, putting newly printed bar code, and processing them as usual. In February 2004, right after introducing reflexive tests by doctors without additional blood sampling, 75 additional requests were made for 50 patients, but they increased gradually up to 1,020 tests for 698 patients in December 2004. In 2005, the monthly average number of tests was 1,035 for 742 patients. CONCLUSIONS: The reflexive tests by doctors without additional blood sampling developed at AMC helped establish a rapid reporting of test results, which in turn reduced LOS related to laboratory. It also increased patient satisfactory indices by reducing repeated blood sampling and would also contribute to the financial health of the hospital.
Automatic Data Processing ; Chemistry ; Chungcheongnam-do ; Edetic Acid ; Hematology ; Humans ; Inpatients ; Length of Stay ; Reflex

BACKGROUND: ABO genotyping is a useful tool in case of ABO discrepancies and in legal medicine. Recent knowledge of various alleles in the ABO gene has led to the need of a different method that can cover numerous polymorphisms. We performed a polymerase chain reaction using sequencespecific priming (PCR-SSP) with 12 primer sets and evaluated its value in the detection of 8 ABO alleles. METHODS: Genomic DNA was isolated from peripheral blood of 222 unrelated Koreans. Sequencespecific primer sets for the nucleotides 261, 297, 467, 802, 803, and 1059 were selected, and 12 PCR reactions were performed for each sample. Direct sequencing was performed to evaluate the accuracy of discrimination between A1(Pro) and A1(Leu) and between O1 and O1v. RESULTS: All the ABO genotype patterns were in an exact match with the ABO phenotypes. The results from sequencing and PCR-SSP were equivalent. The allele frequencies of A1, B, O1, and O1v were 27.25%, 19.82%, 27.25%, and 25.68% respectively. Out of total 121 A1 alleles, 6 (4.96%) were A1(Pro) alleles and 115 (95.04%) were A1(Leu) alleles. No A2, O2, or CisAB alleles were found in this study. CONCLUSIONS: The proportion of O1v allele was similar to that of O1 allele. This was an unexpected result. We developed a method for detecting 8 ABO alleles by PCR-SSP; the method was accurate and was able to discriminate between A1(Pro) and A1(Leu) and between O1 and O1v.
Alleles* ; Discrimination (Psychology) ; DNA ; Forensic Medicine ; Gene Frequency ; Genotype ; Nucleotides ; Phenotype ; Polymerase Chain Reaction

BACKGROUND: Irradiated blood is used to prevent transfusion-associated graft-versus host disease in high risk patients. The guidelines for usage of irradiated blood components vary from one country to other according to their needs. But in Korea, little information is available on the current usage of and the guidelines for irradiated blood. Therefore, we analyzed the usage of irradiated blood components in Hanyang University Medical Center. METHODS: Medical records were reviewed for 187 patients who had been transfused with irradiated blood products during the period from January 2004 to June 2005. And we investigated the proportion of irradiated blood products among the total number of blood products that were transfused during a one-year period. RESULTS: Hematologic diseases and solid cancer patients comprised 63.7% and 24.6% respectively. The proportion of irradiated blood products among the total blood components were 25.7% of platelet concentrates, 61.4% of apheresis platelets, and 5.1% of packed red cells. Total transfused amount by disease categories and the average transfused units per patient of irradiated blood components were high in a group of patients with several hematologic diseases such as acute leukemia. CONCLUSIONS: The use of irradiated blood components takes a great proportion in total blood product transfusions and the majority of blood components were transfused to a group of patients with a few hematologic diseases. The proper use of blood should be guided by the promotion and education of a modified usage protocol for irradiated blood products and by a continuous data analysis.
Academic Medical Centers ; Blood Component Removal ; Blood Platelets ; Education ; Hematologic Diseases ; Humans ; Korea ; Leukemia ; Medical Records ; Statistics as Topic

BACKGROUND: Allergen specific IgE (sIgE) assay is an important aid in the diagnosis and treatment of allergy. We evaluated the analytical performance of a quantitative chemiluminescence immunoassay for sIgE using the continuous random access ADVIA Centaur. METHODS: Six ADVIA Centaur sIgE reagents for common inhalant allergens in Korea, d1, d2, e1, e5, t3, and t7, were evaluated for precision, dilution recovery (parallelism), comparison with Pharmacia UniCAP sIgE assay and skin prick test, sample volume, and analytical speed according to the NCCLS guidelines (I/LA20-A, EP5-A2). Commercialized positive and negative quality control materials were used for a precision study, and samples from a total of 110 patients were used for dilution recovery and comparison studies. RESULTS: Within-run coefficients of variation (CV) of the 6 items were 3.45-6.14% and within-device CVs (total CVs) of all items were below 10%. Interdilutional CVs of all items were 2.84-11.95%, which showed a good linearity and parallelism over its measuring range. Positive/negative concordance rates of the 6 items with UniCAP sIgE assay were 76.3-96.1% (d1, 88.2%; d2, 96.1%; e1, 91.0%; e5, 77.0%; t3, 90.5%; and t7, 76.3%). Concordance rates of the six items with skin prick test were all above 80%. The quantity of sample volume (25 micro L/test) needed was relatively small, and a high throughput (120 tests/hr) and rapid turnaround time (47 min) could be achieved. CONCLUSIONS: The ADVIA Centaur sIgE assay was thought to be a convenient and efficient method to be used in medium- to large-sized laboratories.
Allergens ; Diagnosis ; Humans ; Hypersensitivity ; Immunoassay* ; Immunoglobulin E* ; Indicators and Reagents ; Korea ; Luminescence ; Quality Control ; Skin

Massive intravascular hemolysis secondary to Clostridium perfringens septicemia is rare but often fatal. We report a case of a fatal clostridial hemolytic complication in a 71-year-old woman with probable refractory anemia. The patient was admitted to the emergency room due to a comatose mental state and a high fever. Laboratory analysis showed massive hemolysis. She died from severe anemia two hours after admission. The next day, blood cultures grew gram positive cocci and boxcarshaped gram positive rods, which were identified as coagulase-negative staphylococci and C. perfringens, respectively.
Aged ; Anemia ; Anemia, Refractory ; Clostridium perfringens* ; Clostridium* ; Coma ; Emergency Service, Hospital ; Female ; Fever ; Gram-Positive Cocci ; Gram-Positive Rods ; Hemolysis ; Humans ; Sepsis*

BACKGROUND: The information on the incidence, seasonal variation and clinical pattern of respiratory virus infections is very important for clinicians in managing their patients. This study was aimed to define the epidemiology of respiratory viral pathogens in Seoul and the neighboring areas from March 2004 to February 2006. METHODS: A total of 6,533 specimens were cultured for respiratory viruses during the study period. Madin-Darby canine kidney (MDCK), LLC-MK2, and HEp-2 cells, or R-mix cells (Diagnostic Hybrids Inc., Athens, Ohio, USA) were used for culture. Influenza virus types A & B (Inf A & B), parainfluenza virus (PIV), respiratory syncytial virus (RSV), and adenovirus (ADV) were identified by indirect immuno-fluorescent staining. Medical records of the patients with positive virus cultures were reviewed retrospectively. RESULTS: One or more viral agents were isolated from 1682 specimens (25.7%). The pathogens identified were RSV 37.2%, ADV 19.9%, Inf A 18.9%, PIV 17.5% and Inf B 6.4%. The most frequent pathogen of pneumonia and acute bronchiolitis was RSV and that of croup was PIV. Upper respiratory tract infections were more prevalent in adults and the most frequently caused by influenza virus. Influenza virus itself was more frequently isolated in children less than six years old, which was different from previous reports. Influenza virus was mostly isolated in the winter and spring, while RSV was usually isolated from early fall with a peak incidence in the winter. Inf A and RSV showed a dampening effect on the occurrence of other viruses during their major epidemic. PIV was mostly detected in the spring and summer. ADV was isolated throughout the whole year. CONCLUSIONS: The epidemiological characteristics of respiratory virus infections in Seoul and the neighboring areas in 2004-2006, were similar to the findings of previous reports except for some minor changes. These findings could be useful to clinicians in managing their patients.
Adenoviridae ; Adult ; Bronchiolitis ; Child ; Croup ; Epidemiology* ; Humans ; Incidence ; Kidney ; Medical Records ; Ohio ; Orthomyxoviridae ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory Tract Infections ; Retrospective Studies ; Seasons ; Seoul

BACKGROUND: In many studies, oxidative stress markers have been employed to serve as a measure of a disease process or to reflect oxidative status. These oxidative stress markers must have some degree of predictive validity, but full substantiation of this relation is still lacking. This paper presents data on levels of three biomarkers, oxidized low-density lipoproteins (LDL), carbonyl, and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and a number of life style factors associated with oxidative stress in healthy adults. METHODS: For 237 healthy adults aged 40-60 years, a number of life style factors, biochemical characteristics and oxidative status were evaluated. Markers of oxidative stress were measured by an ELISA method. RESULTS: Waist-hip ratio and use of vitamin supplement were associated with serum oxidized LDL (P<0.05). Body mass index and stress had a relationship (P<0.05) with protein carbonyl. Creactive protein was related to serum oxidized LDL (P<0.01). There was no correlation among three oxidative stress markers, oxidized LDL, carbonyl, and 8-OHdG. CONCLUSIONS: The oxidative stress markers used in this study could not be regarded as a general estimate of the healthy individual oxidative status. Further studies focusing on the development of biomarkers to reflect changes in the oxidative status under normal, non-pathological conditions in humans will be required.
Adult ; Biomarkers ; Body Mass Index ; Deoxyguanosine ; Enzyme-Linked Immunosorbent Assay ; Humans ; Life Style* ; Lipoproteins, LDL ; Oxidative Stress* ; Protein Carbonylation ; Vitamins ; Waist-Hip Ratio