2.Ischemic Stroke Caused by Spontaneous Subclavian Artery Dissection
Woochang CHUN ; Haein BAK ; Sangwon LEE ; Dan A OH ; Cindy W YOON
Journal of the Korean Neurological Association 2018;36(4):393-395
No abstract available.
Stroke
;
Subclavian Artery
3.The Relationship between Anti-Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease and the Rubella Virus.
Seok Jin CHOI ; Dan A OH ; Woochang CHUN ; Sung Min KIM
Journal of Clinical Neurology 2018;14(4):598-600
No abstract available.
Glycoproteins*
;
Oligodendroglia*
;
Rubella virus*
;
Rubella*
4.Analytical Performance Evaluation of Glucose Monitoring System Following ISO15197.
Dongheui AN ; Hee Jung CHUNG ; Hye Won LEE ; Woochang LEE ; Sail CHUN ; Won Ki MIN
The Korean Journal of Laboratory Medicine 2009;29(5):423-429
BACKGROUND: We have evaluated the analytical performance of SureStep Flexx (Johnson and Johnson, USA) which can report the plasma equivalent glucose test results and be connected to the hospital information networks, following ISO15197 analytic procedure for glucometer for the first time. METHODS: Adopting the guidelines of ISO15197, we measured the precision of ten glucometers from their repeatability and intermediate precision, and determined the accuracies of the glucometer, comparing to those of GEM Premier 4000 (Instrumentation Laboratory, USA). In addition, the guidelines of CLSI EP9-A2 and EP6-A were applied to correlate between data of glucometer and those of laboratory reference method by TBA-200FR (Toshiba Medical Systems, Japan) and to examine its linearity of glucose concentrations measured by SureStep Flexx. We used the clinical specimens and commercial control materials. RESULTS: Repeatabilities and intermediate precisions of those glucometers were 4.0-7.3%, and 4.3-6.2%, respectively. When glucose levels are under 75 mg/dL, the difference between results of those meters and the reference values were within +/-6 mg/dL. However when glucose levels are over 75 mg/dL, those differences were within +/-12.7%. These results were acceptable for the ISO15197 criteria in all glucose concentrations. The glucose concentrations showed the clinically relevant linearity in the range from 36 mg/dL to 491 mg/dL. Moreover, Error Grid Analysis showed that all glucose results were in "zone A", which means that these values were clinically accurate. CONCLUSIONS: This study showed that SureStep Flexx can provide reliable results for patients and clinicians to manage the diabetes mellitus, satisfying the ISO15197 criteria.
Blood Glucose/*analysis
;
Blood Glucose Self-Monitoring/*instrumentation/methods/*standards
;
Diabetes Mellitus/blood/diagnosis
;
Humans
;
Quality Control
;
Reference Values
;
Reproducibility of Results
5.Performance Evaluation of the Roche-Hitachi cobas 8000 c702 Chemistry Autoanalyzer.
So Young KIM ; Tae Dong JEONG ; Woochang LEE ; Sail CHUN ; Won Ki MIN
Laboratory Medicine Online 2014;4(3):132-139
BACKGROUND: Optimal operational efficiency requires specific technical solutions such as open, flexible, and adaptable space, suitable equipment requirements, and laboratory instrumentation that combine excellent analytical performance with a capacity for testing large panels in a high throughput manner, under rapid turnaround times. Thus, the aim of this study was to assess the analytical performance of the novel Roche-Hitachi cobas 8000 c702 Chemistry Autoanalyzer. METHODS: Precision, linearity, carry over, detection limits, and comparison studies were performed with 31 routine clinical chemistry tests according to the CLSI guidelines. Commercial quality chemistry control material (Lyphochek, Bio-Rad, USA) and patient sera were used as the test specimens. Unicel DxC instrument (Beckman Coulter, USA) was used as a control analyzer to evaluate the correlation. RESULTS: The total coefficients of variations (CVs) of almost all the analytes were between 0.4 and 4.1%, except for CO2 and ammonia. Excellent linearities were observed in the performance ranges used (r>0.99, slope, 0.961-1.048). Correlations with analogous tests ran on the Unicel DxC instrument were good, correlation coefficients ranging between 0.921 and 1.000. The carryover ranged from -0.216 to 0.481%. CONCLUSIONS: The Roche-Hitachi cobas 8000 c702 Chemistry Autoanalyzer showed satisfactory precision, linearity, carry over, detection limits, and high throughput capacity. The instrument performance correlated well with the Unicel DxC analyzer. We conclude that the balance of elevated throughput and optimal analytical performance should make Roche-Hitachi cobas c702 Chemistry Autoanalyzer suitable for very large clinical laboratories.
Ammonia
;
Chemistry*
;
Clinical Chemistry Tests
;
Humans
;
Limit of Detection
6.Evaluation of Plasma Neutrophil Gelatinase-Associated Lipocalin as a Biomarker for Tubular Damage in Diabetic Nephropathy.
Keumrock HWANG ; Sollip KIM ; Hye Won LEE ; Woochang LEE ; Sail CHUN ; Won Ki MIN
Journal of Laboratory Medicine and Quality Assurance 2012;34(1):31-36
BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) has recently been introduced as a renal biomarker and an increase in its level suggests tubular injury. Diabetic nephropathy, a leading cause of end-stage renal disease, causes typical changes characterized by glomerulosclerosis and eventual tubular damage in the kidney. In the present study, we attempted to validate the usefulness of plasma NGAL (pNGAL) as a biomarker for tubular damage in diabetic nephropathy. METHODS: The plasma NGAL levels of 260 diabetes mellitus patients and 50 healthy individuals werewas measured by means of fluorescent immunoassay using with the Triage NGAL test (Biosite, USA). The patients were divided into 3 groups on the basis of their urinary albumin excretion (UAE) levels, and the pNGAL differences among each group were analyzed. The degree of albuminuria and cystatin C-based glomerular filtration rate (GFR) were also compared with the pNGAL levels. RESULTS: The mean pNGAL levels of the normal subjects and diabetic patients were 61.9 +/- 4.81 ng/mL and 93.4 +/- 71.78 ng/mL, respectively. pNGAL level was significantly increased in patients with severe albuminuria (P < 0.001). The pNGAL level was found to be positively correlated with the degree of albuminuria (R2 = 0.218, P < 0.001) and inversely correlated with GFR (R2 = 0.269, P < 0.001). Particularly, the pNGAL level of patients with diabetic nephropathy was found to be associated with the renal damage and independent of other factors influencing the renal damage (R2 = 0.218). CONCLUSIONS: pNGAL level independently reflects renal damage in patients with diabetic nephropathy. Measurement of pNGAL level combined with UAE would help enable to detect both glomerular and tubular damage in diabetic nephropathy patients.
Albuminuria
;
Diabetes Mellitus
;
Diabetic Nephropathies
;
Glomerular Filtration Rate
;
Humans
;
Immunoassay
;
Kidney
;
Kidney Failure, Chronic
;
Lipocalins
;
Neutrophils
;
Plasma
;
Triage
7.Performance Evaluation of the VISTA 500.
Dae Hyun KO ; Eun Jung CHO ; Woochang LEE ; Sail CHUN ; Won Ki MIN
Journal of Laboratory Medicine and Quality Assurance 2016;38(1):52-57
In this study, we evaluated the performance of a recently developed immunoassay analyser, the VISTA 500 (Siemens, Germany). Precision, linearity, and comparison studies were performed according to the Clinical and Laboratory Standards Institute guidelines. The test items evaluated included IgG, IgA, IgM, C3, C4, ceruloplasmin, prealbumin, transferrin, haptoglobin, rheumatoid factor, anti-streptolysin O, and cystatin C. Commercial control materials (BioRad Laboratories, USA), commercial linearity validation materials (Maine Standards, USA), and patient samples were used for the evaluation. For the correlation study, analysis with a BN-II nephelometer (Siemens) was used as a comparative method. Total coefficients of variation of analytes were found to be between 1.9% and 5.5%. Results of the linearity evaluation were also acceptable for the range tested. Correlations with comparative methods were acceptable. The VISTA 500 analyser showed satisfactory analytical performance with respect to precision, linearity, and comparison. We conclude that the VISTA 500 is likely a good candidate as an immunology analyser.
Allergy and Immunology
;
Ceruloplasmin
;
Cystatin C
;
Evaluation Studies as Topic
;
Haptoglobins
;
Humans
;
Immunoassay
;
Immunoglobulin A
;
Immunoglobulin G
;
Immunoglobulin M
;
Prealbumin
;
Rheumatoid Factor
;
Statistics as Topic
;
Transferrin
8.Evaluation of the Blood Gas Analyzer GEM Premier 4000.
Hee Young CHUNG ; Hee Jung CHUNG ; Sail CHUN ; Woochang LEE ; Won Ki MIN
Journal of Laboratory Medicine and Quality Assurance 2009;31(1):207-214
BACKGROUND: We evaluated the performance of the GEM Premier 4000 (Instrumentation Laboratory, USA), a new blood gas/electrolytes/co-oximetry analyzer, according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. METHODS: Within-run precision, total-run precision, linearity and sample-related carryover were analyzed using quality control materials at three different concentration levels for each analytes. Correlation was compared with the routinely used NOVA CCX2 (Nova Biomedical, USA) with patients' whole blood samples. RESULTS: The within-run and the total-run precisions of the GEM Premier 4000 showed very low CV of 0.04~4.40% and 0.06~4.11%, respectively, in all parameters except the lactate, which had CV of 5.58% in Level 1 QC material. The system showed a good linearity (r2=0.997~1.000, systemic error=0.00~0.20%) for all items. Sample-related carryover was -4.35%~0.15%. In comparison with the NOVA CCX2 instrument, correlation was high in all parameters with the r value ranging from 0.983-0.999 except for carboxyhemoglobin (r=0.804) and methemoglobin (r=0.010) whose concentrations were in the lower level. CONCLUSIONS: GEM Premier 4000 showed good analytical performance required for blood gas analyzer in its precision, linearity, sample-related carryover, and close correlation with NOVA CCX2. It fulfills most of the requirements for both point-of-care and laboratory use.
Carboxyhemoglobin
;
Lactic Acid
;
Methemoglobin
;
Quality Control
9.Installation of Network-Connected Point-of-Care Blood Glucose Meters.
Sung Hee OH ; Tae Dong JEONG ; Woochang LEE ; Sail CHUN ; Won Ki MIN
Journal of Laboratory Medicine and Quality Assurance 2013;35(2):138-142
Point-of-care (POC) testing is desirable because of both the ease with which it can be administered and its short turnaround time. However, because standard POC devices cannot transmit test results automatically to a laboratory information system (LIS), each result must be recorded by hand. This inconvenience not only increases the possibility of clerical errors, but also limits the proper use of test results. If POC test results are not saved in the LIS, it is hard to either monitor patients' health trends or to quality control (QC) the test results. In this paper, we describe how we have solved these problems by connecting 250 POC blood glucose test devices to the LIS via a local area network (LAN). After connecting the POC devices (we used the Accu-Chek Inform II; Roche Diagnostics, Germany) to a manufacturer-provided POC data management system (Roche's Cobas IT 1000; Roche Diagnostics), we developed our own interface program for delivering data from the Cobas IT 1000 system to the LIS. By installing a program to scan the identification barcode worn by patients on their wrists, network-connected POC devices enable users to omit extra ordering, receiving, and recording processes, and they also reduce the possibility of patient misidentification. Such a system also provides an effective way for physicians to follow both the current and accumulated test results of patients. We note that performing QC on glucometers and the sending of data via LAN to the LIS are necessary steps to monitor both patients' results and the QC of those results.
Blood Glucose*
;
Clinical Laboratory Information Systems
;
Glucose
;
Hand
;
Humans
;
Local Area Networks
;
Point-of-Care Systems
;
Quality Control
;
Wrist
10.Performance Evaluation of Beckman Coulter AU5822 Automated Clinical Chemistry Analyzer.
Soo Kyung KIM ; Tae Dong JEONG ; Woochang LEE ; Sail CHUN ; Won Ki MIN
Laboratory Medicine Online 2014;4(2):77-84
BACKGROUND: AU5822 Automated Clinical Chemistry Analyzer (Beckman Coulter, USA) is a fully automated analytical platform designed for the analysis of general chemistry, specific serologic proteins, therapeutic drug monitoring, and drug abuse testing. AU5822 is a high-throughput system that can process up to 5,800 tests per hour and is easy to maintain. In this study, we evaluated the performance of AU5822 on 31 analytes. METHODS: The precision, linearity, correlation, and sample carryover of 31 analytes were evaluated in accordance with the guidelines of the Clinical Laboratory Standards Institute (CLSI). Lyphochek (Bio-Rad Laboratories Inc., USA), Liquichek (Bio-Rad Laboratories Inc.), Validate (Marine Standard Company, USA), and patient sera were used in the analysis. For the correlation study, we carried out a comparison of AU5822 and Cobas 8000 Modular Analyzer (Roche, Switzerland). RESULTS: The coefficients of variation of all samples showed values below 5%. The coefficient of determination (R2) was > or =0.99, with linearity in the clinically important range. The comparison with Cobas 8000 showed a good correlation, with a correlation coefficient of >0.975 for all of the analytes, excluding sodium that had a correlation coefficient of 0.9641. The test values of percentage sample carryover were less than 0.89%. CONCLUSIONS: AU5822 performed well in terms of precision, linearity, comparison, and sample carryover in the established assays for 31 analytes. Therefore, Beckman Coulter AU5822 Automated Clinical Chemistry Analyzer is expected to be useful for routine chemistry analysis in hospitals with large test volumes.
Chemistry
;
Chemistry, Clinical*
;
Drug Monitoring
;
Humans
;
Sodium
;
Statistics as Topic
;
Substance Abuse Detection