The relationship between low density lipoprotein subclasses and lipoprotein(a) in patients with liver cirrhosis

학위논문(박사)--서울대학교 대학원 :의학과 임상병리과학전공,2002.Docto

한국인의 아포지단백 E 유전형과 혈청 지질 성분과의 관련성

학위논문(석사)--서울대학교 대학원 :의학과 임상병리학전공,1996.Maste

The Frequency of Discordant Variant Classification in the Human Gene Mutation Database: A Comparison of the American College of Medical Genetics and Genomics Guidelines and ClinVar

Objective: Discordant variant classifications among public databases is one of the well-documented limitations when interpreting the pathogenicity of variants. The aim of this study is to investigate the level of germline variant misannotation from the Human Gene Mutation Database (HGMD) and the annotation concordance between databases. Methods: We used a total of 188,106 classified variants (disease-causing mutations [n = 179,454] and polymorphisms [n = 8652]) in 6466 genes from the HGMD. All variants were reanalyzed based on the American College of Medical Genetics and Genomics (ACMG) guidelines and compared to ClinVar database variants. Results: When variants were classified based on the ACMG guidelines, misclassification was observed in 3.47% (2289/65,896) of variants. The overall concordance between HGMD and ClinVar was 97.62% (52,499/53,780) of variants studied. Conclusion: Variants in databases must be used with caution when variant pathogenicity is interpreted. This study reveals the frequency of misannotation of the HGMD variants and annotation concordance between databases in depth

Evaluation of Two Safety Syringes for Arterial Blood Gas Analysis

배경: 동맥혈가스분석은 생명이 위급한 환자에게 혈액가스 및 산-염기 평형, 전해질 수치를 제공하는 매우 중요한 검사이며 정확한 결과가 요구된다. 동맥혈가스분석용 주사기의 여러 요인이 결과에 영향을 미칠 수 있지만 주사기를 도입하기 전에 이를 평가하는 임상 검사실은 거의 없다. 우리는 임상 검사실에서 널리 사용되고 있는 동맥혈가스분석용 안전주사기인 Greenmedi 헤파린안전주사기(GRS; SANG-A FRONTEC, Korea) 및 Portex 동맥혈용안전주사기(POS; Smiths Medical, USA)에 대해 성능을 평가하였다. 방법: 서울아산병원 진단검사의학과 중앙검사실로 접수된 검체를 대상으로 응괴 발생률, 용혈 발생률을 평가하였고, 3가지 농도의 정도관리물질을 사용하여 가스투과도, 검체량에 의한 영향, 정밀도, 일치도를 평가하였다. 정도관리물질을 실온 보관 후 pO2, pCO2, pH를 측정하여 가스 투과도를 평가하였고. 여러 용량의 정도관리물질로 검체량에 의한 영향을 평가하였다. 검사를 반복하여 정밀도를 평가하였고, 두 주사기의 결과값의 일치도를 분석하였다. 결과: 응괴 발생률은 호흡기내과 일반병동에서 GRS로 채취했을 때 1.07% (51/4,769)로 허용범위를 넘었고, 중환자실에서 POS로 채혈했을 때 0% (0/387)였다. 용혈 발생률은 GRS 14.9% (14/94), POS 10.0% (8/80)로 둘 다 허용범위보다 높았다. GRS, POS 주사기 둘 다 최대허용보관시간은 10분 미만이며, 최소허용검체량은 0.6 mL 초과였다. 정밀도는 모두 우수한 결과를 보였으나 pO2는 두 주사기 간 비교적 낮은 일치도를 보였다. 결론: 두 제품 모두 정밀도는 우수하였으나, 용혈 발생률이 높았다. 또한 결과값의 낮은 상관관계 및 보관시간 및 채취용량에 의한 영향도 확인되었으므로 사용 시 유의해야 한다. 각 검사실에서는 주사기를 도입 전에 주사기의 품질 평가를 선행할 것을 제안한다. Background: Arterial blood gas (ABG) analysis is a crucial test providing vital information for patients who are critically ill. Accurate results are essential; however, pre-implementation evaluation of ABG syringes is uncommon. We evaluated the performance of the Greenmedi heparin syringe (GRS; SANG-A FRONTEC, Korea) and the Portex arterial blood sampling kit (POS; Smiths Medical, USA), which are widely used in clinical laboratories. Methods: Samples from Asan Medical Center were assessed for clotting rate and hemolysis rate. Gas permeability, sample volume impact, precision, and concordance were evaluated using quality control materials. Gas permeability was assessed by measuring pO2, pCO2, and pH after storing the materials for different time periods. The influence of sample volume was tested at various quantities. Precision was evaluated through repeated tests, and concordance between the two syringes’ results was analyzed. Results: GRS had a clotting rate of 1.07% (51/4,769), exceeding the acceptable range, whereas POS had no clotted samples (0/387). Hemolysis rates were 14.9% (14/94) for GRS and 10.0% (8/80) for POS, both higher than the acceptable rate. Both syringes had a storage time of less than 10 minutes and required a minimum sample volume above 0.6 mL. Precision was noteworthy, but there was a relatively weak concordance between pO2 values obtained with the two syringes. Conclusions: Both syringes demonstrated notable precision but had high hemolysis rates. Results showed low concordance and were influenced by storage time and sample volume. Caution should be exercised when using these syringes, and it is recommended to assess their quality before implementation in each laboratory

Standardization Status of Total Cholesterol Concentration Measurement: Analysis of Korean External Quality Assessment Data

Background: Total cholesterol concentration measurement is important in the diagnosis of dyslipidemia and evaluation of cardiovascular disease risk factors. Measurement reliability for obtaining an accurate total cholesterol concentration requires procedure standardization. We evaluated the standardization status for total cholesterol concentration measurement through Korean external quality assessment (EQA) data analysis. Methods: This study involved 1,670 laboratories that participated in the EQA of total cholesterol concentration measurements in 2019 for 32 products from different manufacturers. The target concentrations of three quality control (QC) materials (samples A, B, and C) were measured using the reference method and compared with EQA data. The performance criteria for total cholesterol concentration measurement were based on the National Cholesterol Education Program guidelines, with +/- 3% inaccuracy. Results: The target values and inaccuracies of the QC material based on the reference method measurements were 254.65 +/- 7.64, 108.30 +/- 3.25, and 256.29 +/- 7.69 mg/dL (6.59 +/- 0.20, 2.80 +/- 0.08, and 6.63 +/- 0.20 mmol/L) for samples A, B, and C, respectively. The performance criteria were not met in 42.7% laboratories for sample A, 68.4% of laboratories for sample B, and 38.0% laboratories for sample C. Conclusions: Despite significant efforts to accurately measure total cholesterol concentrations, further actions are needed for measurement standardization. Manufacturers reporting values that differ from target values should check calibrator traceability; additional efforts to accurately measure total cholesterol concentrations are required for laboratories that use products from these manufacturers

Performance of Tacrolimus Electrochemiluminescence Immunoassay on Cobas Pure Integrated Solutions

Background: Cobas pure integrated solutions (Roche Diagnostics International AG, Switzerland) is a newly launched automatic analyzer combining clinical chemistry, immunoassay, and ion-selective electrode diagnostic testing. We evaluated the analytical performance of tacrolimus electrochemiluminescence immunoassay (ECLIA) on cobas pure and compared it with that of affinity chrome-mediated immunoassay (ACMIA) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Methods: Quality control materials and residual whole blood samples from patients receiving tacrolimus were used in evaluating the performance metrics, including the precision, linearity, comparison, and carryover, of tacrolimus ECLIA (Roche Diagnostics GmbH, Germany) on cobas pure. The precision, linearity, and comparison were assessed in accordance with Clinical and Laboratory Standards Institute guidelines EP5-A3, EP6-A, and EP9-A3, respectively, and the carryover was calculated. Results of tacrolimus ECLIA on cobas pure were compared with those of tacrolimus ACMIA (Siemens Healthineers, USA) and LC-MS/MS (Waters Corporation, USA) on other platforms. Results: The within-laboratory precisions of tacrolimus ECLIA on cobas pure were 4.0%, 3.1%, and 3.2% at low, medium, and high concentrations of quality control materials. The linearity of the assay was acceptable (0.91-27.43 ng/mL). Correlation analysis indicated that the results of tacrolimus ECLIA on cobas pure were comparable to those of Dimension TAC and LC-MS/MS (r=0.977 and 0.994, respectively) with slight difference. Moreover, the carryover effect was 0.03%. Conclusions: Tacrolimus ECLIA on cobas pure showed acceptable precision, linearity, and correlation with ACMIA and LC-MS/MS except for a slight difference. The overall performance of tacrolimus ECLIA on cobas pure is suitable for the therapeutic drug monitoring of tacrolimus in clinical laboratories

Schemes and Performance Evaluation Criteria of Korean Association of External Quality Assessment (KEQAS) for Improving Laboratory Testing

External quality assessment (EQA) is important for evaluating clinical laboratories and enhancing their testing quality. EQA schemes are variable; thus, it is crucial that the EQA organizers share their experiences to continuously improve the EQA scheme. The Korean Association of External Quality Assessment Service (KEQAS) has been the leading, authorized EQA institute for the standardization and quality management of laboratory testing in Korean medical institutions since 1976. The EQA scheme underwent a major change in 2016, and the number of EQA programs increased significantly since then. The key changes implemented in EQA scheme include a fully computerized assessment to accelerate feedback and unification of the testing and reporting methods. We provide an overview of the EQA schemes and performance evaluation criteria of the KEQAS and suggest directions for achieving the global harmonization of EQA

Recent Trends in Creatinine Assays in Korea: Long-Term Accuracy-Based Proficiency Testing Survey Data by the Korean Association of External Quality Assessment Service (2011-2019)

Background: Accurate serum creatinine (Cr) concentration measurement is essential for evaluating kidney function. In 2011, the Korean Association of External Quality Assessment Service (KEQAS) launched an accuracy-based Cr proficiency testing (ABCr PT) survey. We analyzed long-term data of the KEQAS ABCr PT survey collected between 2011 and 2019 to assess recent trends in Cr assays in Korea. Methods: The ABCr PT survey including three commutable fresh-frozen serum samples was performed twice a year. The target Cr concentration was assigned using isotope-dilution mass spectrometry. We analyzed data obtained from the participating laboratories, calculated the yearly bias, and evaluated bias trends for the major reagents and instruments. Outliers were excluded from all analysis. Results: The mean percentage bias based on the total data of all participating laboratories was 10.8% in the 2011-A survey and 0.2% in 2019-B survey. Bias for the major reagents and instruments differed depending on the manufacturer. Enzymatic assays generally showed desirable bias ranging from -3.9% to 3.2% at all Cr concentrations and lower interlaboratory variability than non-enzymatic assays (enzymatic vs. non-enzymatic, 3.3%-7.2% vs. 6.3%-9.1%). Conclusions: Although the mean percentage bias of Cr assays tends to decrease over time, it is necessary to continuously strive to improve Cr assay accuracy, especially at low concentrations