INTRODUCTION: Estimation of the risk of Down syndrome pregnancy by the triple marker test is performed on women once at anytime during the 15-21 weeks of gestational age. The triple marker test is based on the distribution of the alpha-fetoprotein (AFP), chorionic gonadotropin (CG) and unconjugated estriol (uE3) of the different pregnancy. In spite of the logical excellencies, various factors can affect the result of the test in practical field. We compared differences of the risk of Down syndrome pregnancy based on the specimen obtained from two visits during the 15-21 weeks of gestational age. METHOD: We measured the AFP, CG and uE3 with Access (Beckman Coulter, USA) from the sera of 104 pregnant women who visited two times about 2 weeks of interval during 15-21 weeks of gestational age. We calculated log (MoM) of AFP, CG and uE3 of each marker between two visits, and compared differences of each biochemical marker and difference of risk of Down syndrome pregnancy between two visits. RESULT: Mean+/-SD of log (MoM) of AFP, CG, uE3 of the 1st visit were 0.019+/-0.156, -0.016+/-0.224, 0.002+/-0.138, respectively, and those of AFP, CG, uE3 of the 2nd visit were 0.010+/-0.140, -0.076+/-0.205, 0.057+/-0.138, respectively. CG and uE3 showed statistically significant difference (P<0.001, P<0.001, respectively) but AFP did not (P=0.328). Risk of Down syndrome pregnancy of the 1st visit was 8.017x10(-4)+/-1.6241x10(-3), and that of the 2nd visit was 5.667x10(-4)+/-1.6241x10(-3), with no significant difference statistically (P=0.094). CONCLUSION: The risk of Down syndrome based on the sera of woman who visited two times about 2 weeks of interval between 15-21 weeks of gestational age did not show significant difference. It is resonable that triple marker test is performed on women once at anytime during the 15-21 weeks of gestational age in practical base.
alpha-Fetoproteins ; Biomarkers ; Chorionic Gonadotropin ; Down Syndrome* ; Estriol ; Female ; Gestational Age ; Humans ; Logic ; Mass Screening* ; Pregnancy ; Pregnant Women

BACKGROUND: In the process of implementing the nucleic acid amplification tests (NAT) for the blood screening, it was needed to change plain tube to EDTA tube for the sampling. Because the sample is taken from the CPDA-1 anticoagulated whole blood, the EDTA of tube could be mixed with the CPDA-1. So, we studied the effect of the mixing of two anticoagulants on the NAT. METHODS: Using HIV-1 and HCV RNA standards, we made the qualitative and quantitative test panels for the EDTA anticoagulant and the EDTA/CPDA-1 anticoagulant containing blood. The reverse transcription-polymerase chain reaction of Roche and transcription-mediated amplification of Chiron were used for the RNA qualitative and quantitative test. RESULTS: On the qualitative HIV-1 and HCV RNA tests for the EDTA, CPDA-1 alone and the CPDA-1/EDTA mixture, false negative and false positive reactions were not observed. On quantitative test, viral loads were not different statistically. CONCLUSIONS: Since there were no statistically significant differences between CPDA-1 alone and EDTA/CPDA-1 mixture in both qualitative and quantitative tests for HIV-1 and HCV RNA, it was concluded that mixing of anticoagulants, EDTA and CPDA-1, would not cause an significant effect on the NAT for the donated blood.
Anticoagulants ; Edetic Acid ; False Positive Reactions ; HIV-1 ; Mass Screening ; Nucleic Acid Amplification Techniques* ; RNA ; Viral Load

BACKGROUND: This study was performed to investigate on the genotypic frequencies of p53 Arg72Pro polymorphism and the prevalence of p53 codon 249 mutation in hepatocellular carcinoma patients. METHODS: Plasma DNAs were extracted from the samples of 44 early HCC cases, 24 chronic B-viral hepatitis patients and 27 healthy individuals. Serum levels of AFP, PIVKA-II, and HBV DNA-positive rates among the study groups were also compared. PCR-based restriction fragment length polymorphism method was used to determine p53 Arg72Pro genotype and to detect codon 249 mutation. RESULTS: Serum AFP and PIVKA-II level, Edmondson grade, tumor size and frequency of HBV DNA-positivity among HCC group according to Arg72Pro genotypes showed no statistically significant difference. The frequencies of Arg72Pro genotypes (Arg/Arg, Arg/Pro, Pro/Pro) were respectively as follows: 34.1%, 47.7%, 18.2% in HCC group; 29.2%, 54.2%, 16.7% in hepatitis group; 29.6%, 55.6%, 14.8% in control group. Pro homozygote genotype had a higher risk for developing HCC by adjusted OR (1.529, 95% CI 0.325-7.193), but not statistically significant (P=0.591). No codon 249 mutation was found among 44 HCC cases. CONCLUSIONS: Pro homozygote was around 16% in all study groups, and did not statistically increase risks to developing HCC. We suggest that Arg72Pro polymorphism of p53 gene is not a significant risk factor in early hepatocarcinogenesis.
Biomarkers ; Carcinoma, Hepatocellular ; Codon ; DNA ; Exons ; Genes, p53 ; Genotype ; Hepatitis ; Hepatitis B ; Hepatitis B virus ; Homozygote ; Humans ; Plasma ; Polymorphism, Restriction Fragment Length ; Prevalence ; Protein Precursors ; Prothrombin ; Risk Factors

BACKGROUND: Lot-to-lot reagent reproducibility is an important issue in immunoassays. However, there have been no universal criteria for acceptable lot-to-lot reproducibility. We sought to evaluate the inter-lot reagent difference by analyzing the results of various quality control materials during a certain period of time. METHODS: The results of control materials using different reagent lots and same control lots for immunoassays of HBsAg, anti-HBs, alpha-fetoprotein (AFP), ferritin, and CA 19-9 were analyzed. The average value, standard deviation, and coefficient of variation obtained from each reagent lot were calculated and differences in mean control values between two different reagent lots were assessed. We also analyzed the difference between the last control result using one reagent and the first control result using a new reagent. RESULTS: There was no significant difference in control values among reagent lots during this study period in all immunoassays of HBsAg, anti-HBs, AFP, ferritin, and CA 19-9. Some of the reagents showed statistical differences in QC values, but the difference was not considered clinically different. Also, at the time of reagent lot change, there was no significant difference in reagent parallel tests. CONCLUSIONS: Lot-to-lot reagent variation was not significant in immunoassays evaluated in this study. However, this study has been performed during relatively short period by one to three reagent lot changes, parallel testing should be continuously checked at reagent lot changes in each laboratory for continuous quality assurance. These results can be used as basic data for setting the criteria of acceptance on inter-lot difference in reagent parallel tests.
alpha-Fetoproteins ; Collodion ; Ferritins ; Hepatitis B Surface Antigens ; Immunoassay ; Indicators and Reagents ; Quality Control ; Retrospective Studies

BACKGROUND: Fecal occult blood tests have been widely used for colorectal cancer screening. In recent years, many laboratories have used automated fecal occult blood test analyzers using immunologic techniques for convenience, fast reporting and quantitative handling. Hemo Techt NS-Plus C15 (NS-Plus C) (Alfresa pharma Co., Japan) is a newly-introduced automated fecal occult blood test analyzer using colloidal gold agglutination methods. We evaluated the performance of NS-Plus C. METHODS: The linearity, precision and carry-over rate of NS-Plus C were evaluated. We performed parallel test between NS-Plus C and HM-JACK (Kyowa Medix Co., Japan) using 219 stool specimens. RESULTS: The linearity was good (R2=0.998) and coefficient of variation (CVs) of within-day precision were 2.61% and 2.07% in low and high concentration, and between-day CVs for each group were 3.18% and 1.63%, respectively. Carry over rate was 0% and concordance rate between NS-Plus C and HM-JACK was 98.6%. CONCLUSIONS: NS-Plus C showed good performance for linearity, precision, carry over rate and comparison study. Therefore, this is believed to be a highly reliable measurement system for fecal occult blood test.
Agglutination ; Colorectal Neoplasms ; Gold Colloid ; Handling (Psychology) ; Immunologic Techniques ; Mass Screening ; Occult Blood

BACKGROUND: Point-of-care testing (POCT) glucometers are widely being used for management of diabetes. We examined the analytical performance of the recently developed glucometer CareSens(R) N Glucometer (i-SENS Inc., Korea). METHODS: CareSens N was evaluated for linearity, precision, and the effect of hematocrit. Method comparison using the laboratory reference method, hexokinase method by Hitachi 7600 (Hitachi Co., Japan) was also performed. Other glucometers, Accu-Chek(R) inform (Roche Diagnostics LTD., Germany) and Onetouch(R) ultra(TM) (Lifescan Inc., USA) were evaluated for the same categories according to CLSI guidelines. RESULTS: CareSens N Glucometer showed a good linearity and precision. The linearity was r=0.9965. The coefficients of variations (CVs) of within-run precision were 0.73-1.98% and CVs of total precision were 1.65-2.71%. A high correlation (glucose by CareSens N = 0.9767 x glucose by Hitachi 7600 + 4.1734, r=0.9614) was also shown between the CareSens N glucometer and Hitachi 7600 in the central laboratory. Other glucometers showed a good linearity. The within-run and total-run CVs of other glucometers were within 10%. Although differences with the reference method were within allowable ranges, all glucometers showed variable bias compared with the reference method. Overestimation or underestimation of glucose values were observed by change of hematocrit in range of 31.1 to 51.2%. CONCLUSIONS: CareSens N showed good linearity, precision, and correlation with reference method. CareSens N provided reliable result of blood glucose and seems appropriate for clinical use in the management of diabetic patients.
Bias (Epidemiology) ; Blood Glucose ; Glucose ; Hematocrit ; Hexokinase ; Humans ; Korea

BACKGROUND: We evaluated the HbA1c assay on COBAS INTEGRA 800 Closed Tube System (Roche Diagnostics, USA). METHODS: Precision was determined following Clinical and Laboratory Standards Institute (CLSI) EP5-A2 using the Lyphochek Diabetes Control (Bio-Rad Laboratories, Canada). Two levels of QC materials were assayed in duplicates at two separate times per day for 20 days. The within-run, between-run and between-day precisions were evaluated. We compared the HbA1c of COBAS INTEGRA 800 Closed tube system using Tina quant Hemoglobin A1c Gen.2 (Roche Diagnostics, Germany) reagent with Variant II Turbo (Bio-Rad Laboratories, USA). Bias was determined following CLSI EP9-A2. RESULT: The HbA1c assay on COBAS INTEGRA 800 Closed Tube System showed excellent precision performance: at a level of 5.9%, total, between run, and between day CVs were 1.8%, 0.5%, and 1.6%, respectively. At a level of 9.6%, total, between run, and between day CVs were 1.4%, 0.3%, and 1.1%, respectively. The assay correlated well with the Variant II Turbo (y=0.9x+0.53, r2=0.9857). Mean bias against Variant II Turbo was -0.2%. Compared with Variant II Turbo, the estimate of the predicted bias at a given medical decision level (HbA1c at 6% and 9%) was -0.1% and -0.31%, respectively. CONCLUSIONS: The COBAS INTEGRA 800 Closed Tube System HbA1C assay was precise and equivalent to Variant II Turbo.
Bias (Epidemiology) ; Hemoglobins

BACKGROUND: Hemoglobin A1c (HbA1c) is widely used for the monitoring of glycemic control in diabetes mellitus patients. Various methods are applied for the determination of HbA1c levels. Recently, a novel National Glycohemoglobin Standardization Program (NGSP)-certificated reagent (AutoLab HbA1c, IVD-LAB, Korea) was introduced for use in an automated chemistry analyzer. We evaluated the analytical performance of this immunoturbidimetry reagent and compared it with the ion-exchange high performance liquid chromatography (Variant II Turbo, Bio-Rad Laboratories, Inc., USA) and immunoassay (Cobas Integra 800, Roche Diagnostics, Germany) methods. METHODS: Toshiba 200FR NEO (Toshiba Medical Systems Co., Japan) with the AutoLab reagent was evaluated for precision, linearity, carryover and compared with Cobas Integra and Variant II Turbo. RESULTS: Coefficients of variation (CVs) of within-run imprecision for low and high level were 1.8% and 0.7%, respectively. CVs of within-laboratory imprecision for low and high level were 2.4% and 1.0%, respectively. The linearity was excellent with R2 = 0.99 in the range of 3.05-15.50%. It was well correlated with Variant II Turbo (R=0.9904) and Cobas Integra 800 (R=0.9992). The carryover rate was 0.4%. CONCLUSIONS: The Toshiba 200FR NEO with the AutoLab reagent showed excellent precision and linearity and minimal carryover rate. It was well correlated with the other widely used methodological instruments. It may be used for the diagnosis and the treatment monitoring of diabetes.
Chromatography, Liquid ; Diabetes Mellitus ; Hemoglobins ; Humans ; Immunoassay

BACKGROUND: In Korea, 17-alpha-hydroxyprogesterone (17-OHP) neonatal screening for congenital adrenal hyperplasia (CAH) has a high false positive rate. Preterm infants have higher levels of 17-OHP than term infants. We established the separate cutoff values of 17-OHP under the guideline of the Clinical and Laboratory Standard Institute C28-A3 to reduce a false positive rate. METHODS: The 17-OHP enzyme-immunoassay was used in blood spots of 22,601 newborns. To decide whether to partition cutoff values based on sex, sampling date and birth weight was assessed by Z-test and standard deviation (SD) ratio. If the result was significant, we estimated the cutoff value with 90% confidence intervals (CIs) using the nonparametric method. RESULTS: In the subclasses based on sex and sampling date, the results were not significant. However, the birth weight-adjusted subclasses (SD ratio > 1.5) showed that it was necessary to distinguish low-birth-weight infants from the others. We selected the subclass categories to reflect the concept of low- or very-low-birth-weight infant. The maximum percentile to define a 90% CI was chosen in each subclass. After applied the re-estimated cutoff value, the recall rate was decreased from 0.6% to less than 0.2%. CONCLUSIONS: The birth weight-adjusted cutoff value of 17-OHP in neonatal screening for CAH can be reduced the false positive rate of low-birth-weight infants. This approach would decrease unnecessary blood draws, medical evaluation, parental anxiety and burden on health care resources.
17-alpha-Hydroxyprogesterone ; Adrenal Hyperplasia, Congenital ; Anxiety ; Birth Weight ; Delivery of Health Care ; Humans ; Infant ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Premature ; Infant, Very Low Birth Weight ; Korea ; Neonatal Screening ; Parents ; Parturition

BACKGROUND: Plasma specimens are recently used instead of serum in clinical chemistry to improve (test result turnaround time, TAT). We evaluated the performance of lithium heparin gel plasma separating tube in comparison to existing vacutainer gel serum tube in common clinical chemistry assays. METHODS: Total 52 subjects who had visited the health promotion center were included in the study. Lithium heparin plasma tubes and serum tubes were tested for 30 clinical chemistry items and 3 cardiac markers. Test results were analyzed by calculation of mean bias and percent difference. RESULTS: The performance of the lithium heparin plasma tube was considered to be clinically equivalent to the serum tube for all assays except for potassium. The difference of potassium levels between lithium heparin plasma tube and the serum tube was -7.32%. Test results of some analytes including glucose, lactate dehydrogenase, total CO2 and potassium using the lithium heparin tube were significantly changed after 24 hours of storage. CONCLUSIONS: The lithium heparin plasma tube provided acceptable results comparison to the existing serum separating tube in common clinical chemistries and can be used for reducing, TAT. However, the stability of plasma gel tubes on 24 hours of storage was unstable in some analytes, it requires attention.
Bias (Epidemiology) ; Chemistry, Clinical ; Glucose ; Health Promotion ; Heparin ; L-Lactate Dehydrogenase ; Lithium ; Plasma ; Potassium