BACKGROUND: Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis(HD) for end stage renal disease(ESRD). After renal failure, antioxidant levels increase, possibly in response to increased generation of free radicals. As a result, increased lipid peroxidation may contribute to increased risks of atherosclerosis. The aims of this study was to investigate the distribution of total antioxidant capacity of plasma in Korean adults and ESRD patients, and effects of HD. METHODS: Ninety five patients(41 men and 54 women, mean ages 54.7+/-28.3 years) receiving regular HD for ESRD were recruited. Venous blood samples were taken immediately before HD in 65 patients, and before and after HD in 30 patients. Control subjects were healthy individuals(61 men and 51 women, mean ages 42.7+/-10.8 years). Total antioxidant capacity of plasma and serum uric acid concentration were assessed. RESULTS: Reference range of plasma total antioxidant capacity in Korean population is 1.04 ~ 1.52 mmol/L. Total antioxidant capacities in male(1.32+/-0.11 mmol/L; mean+/-SD) were higher than those of female(1.24+/-0.12 mmol/L, P<0.001). Total antioxidant capacities in ESRD patients(1.72+/-0.26 mmol/L) were higher than controls(1.28+/-0.12 mmol/L, P<0.001). Total antioxidant capacities in pre-HD samples(1.55+/-0.16 mmol/L) were higher than post-HD(1.33+/-0.10 mmol/L). Plasma total antioxidant capacities and serum uric acid concentrations showed positive correlation(r = 0.69, P < 0.0001). DISCUSSION: The increase in total antioxidant capacity in ESRD patients might be due to high serum uric acid. Plasma total antioxidant capacities decreased after HD in ESRD patients due to decrease of uric acid concentration.
Adult ; Atherosclerosis ; Cardiovascular Diseases ; Female ; Free Radicals ; Humans ; Kidney Failure, Chronic* ; Lipid Peroxidation ; Male ; Mortality ; Plasma ; Reference Values ; Renal Dialysis* ; Renal Insufficiency ; Uric Acid

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

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

As the Therapeutic Drug Monitoring Subcommittee (TDMS) of the Korean Association of Quality Assurance for Clinical Laboratories (KAQACL), we organised two trials as an external quality assessment of therapeutic drug monitoring (TDM) and testing for drugs of abuse (DOA) in 2014. In each trial, low and high level control materials for TDM testing, and positive and negative control materials for DOA testing, were requested from institutions. The number of participating laboratories was 107 for the first trial and 106 for the second. The average number of drug items provided was 5.7 per institution. The most commonly tested substances were, in descending order, valproic acid, digoxin, tacrolimus, phenytoin, and vancomycin. The mean inter-laboratory coefficients of variation for low- and high-level TDM control materials were 8.5% and 7.2%, respectively. The most widely used TDM analysers were the Architect i System (Abbott Diagnostics, USA), followed by the Cobas Integra (Roche Diagnostics, Switzerland) and the Cobas c501 analyser (Roche Diagnostics). The number of participating laboratories for DOA testing was 23% higher that than in 2013. In 96.9% of cases, our analysis confirmed the suitability of the tests at participating DOA laboratories in both trials. In the external quality assessment of TDM by the TDMS of KAQACL in 2014, the overall performance of TDM testing was found to be similar to that observed in the previous years, and inter-laboratory precision was higher than that in 2013. Continuous quality improvement of TDM testing by participation in a proficiency-testing program is necessary.
Digoxin ; Drug Monitoring* ; Korea ; Laboratory Proficiency Testing ; Phenytoin ; Quality Improvement ; Street Drugs* ; Tacrolimus ; Valproic Acid ; Vancomycin

No abstract available.
Drug Monitoring ; Sirolimus ; Tacrolimus

BACKGROUND: National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) is the guideline for detection evaluation, and treatment of high blood cholesterol in adults. The risk of coronary heart disease (CHD) is assessed by the presence of CHD risk equivalents and the number of risk factors. LDL-cholesterol is the goal of treatment for hyperlipidemia. Contents: The most common approach for determining LDL-cholesterol level in clinical laboratory is to calculate it based on Friedewald formula. For accurate risk assessment by the calculated LDL-cholesterol, good analytical performances of total cholesterol, HDL-cholesterol and triglyceride are prerequisite. Even if the analytical performance of these three analytes are within the acceptable criteria, pooled imprecision and bias of the calculated LDL-cholesterol could not meet the criteria for LDL-cholesterol. Even under conditions satisfying the requirements of Friedewald formula, the calculated LDL-cholesterol level was lower than the directly measured level and the difference was dependent on the level of triglyceride, LDL-cholesterol and total cholesterol. When evaluatingpatients with hyperlipidemia, Friedewald calculation may underestimate the risk for coronary heart disease which may lead to inappropriate treatment option. CONCLUSIONS: When evaluating patients with hyperlipidemia, direct measurement of LDL-cholesterol appears to be better than Friedewald calculation.
Adenosine Triphosphate ; Adult ; Bias (Epidemiology) ; Cholesterol ; Coronary Disease ; Humans ; Hyperlipidemias ; Lipoproteins ; Risk Assessment ; Risk Factors

Serum creatinine has been widely used clinically as an important index for kidney function. Kinetic Jaffe assay is used for serum creatinine analysis at about 80% of clinical laboratories in Korea. There are two major interferences when creatinine level is measured by kinetic Jaffe method. One is Jaffelike chromogen, which causes positive interference, and the other is bilirubin that creates negative interference. Positive interference created by Jaffelike chromogen can be easily corrected by subtracting 0.3 mg/dL (arithmetic compensation), which is average interference by Jaffelike chromogen in normal serum, from the measured creatinine value by kinetic Jaffe method. The interference created by bilirubin can be eliminated by rate blanking which corrects the rate of change in absorbance by bilirubin from the absorbance change by Jaffe reaction. Compensated rate-blanked Jaffe kinetic assay employs above two major corrections. In clinical laboratories currently using kinetic Jaffe Method, simple application of "compensated rate-blanked Jaffe kinetic assay" can determine serum creatinine values that minimizing major interferences without change of reagent.
Bilirubin ; Creatinine ; Kidney ; Korea

BACKGROUND: Oxidative stress, lipid peroxidation and immune response to oxidized low density lipoprotein(oxLDL) are important events in the progression of atherosclerosis in diabetes mellitus(DM). Though, many clinical studies used man-made reagents that the reproducibility of the tests was not reliable and showed controversial results in some aspects. We performed above three tests in DM patients by the commercial kits and compared our results with previous results. METHODS: Total 67 DM patients and sex- and age-matched healthy persons were tested about total antioxidant status(TAS), lipid peroxidation(LPO) and autoantibody to oxLDL(anti-oxLDL) by Total Antioxidant Status kit(RANDOX Labs., Crumlin, UK), BIOXYTECH LPO-586 kit(OXIS International Inc., Portland, OR, USA) and Ox-LDL IgG ELISA kit(BIODESIGN International, Kennenbunk, ME, USA) each. RESULTS: The intra-run and between-run coefficients of variation of TAS and LPO were 2.6/2.7% and 13.4/15.6% respectively. The intra-run coefficient of variation of anti-oxLDL was 1.8 to 6.9%. DM patients showed decreased TAS(1.31+/-0.15 mmol/L) when compared with normal controls(1.38+/-0.09 mmol/L, P <0.01). TAS was inversely correlated with HbA1c(r=-0.38, P <0.01). LPO and anti-oxLDL in DM patients did not differ significantly from normal controls. CONCLUSIONS: By commercial kits, we could get reproducible results of TAS and anti-oxLDL, but not LPO test. The results of TAS and HbA1c among the DM patients and normal controls suggested that poor glycemic control might be associated with decrease of TAS. We could not find significant difference in the results of LPO and anti-oxLDL between two groups.
Atherosclerosis ; Diabetes Mellitus* ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Indicators and Reagents ; Lipid Peroxidation* ; Lipoproteins* ; Oxidative Stress

BACKGROUND: Synchron LX20(Beckman Coulter, Fullerton, USA) is an automated chemical analyzer introduced in 1998. It is still not completely evaluated on clinical fields, is set in the Asan Medical Center for the first time in Korea. We evaluated the performance of the analyzer before routine use to prevent critical errors, to confirm the manufacturer's instructions, and to establish a specific data system for our institute. METHODS: For glucose, BUN, creatinine, total protein, albumin, uric acid, cholesterol, total bilirubin, direct bilirubin, ALT, AST, LD, gamma-glutamyltransferase(gamma-GT), CK, amylase, lipase, Na, K, Cl, CO2, Ca, phosphorus and Mg, within-day precision, between-day precision, degree of correlation, linearity, recovery rates and reportable ranges were completely or partly analyzed. Specimen selection, specimen preparation and the statistical methods followed the guidelines of National Committee for Clinical Laboratory Standards as much as possible. The calculations were performed with computer software, EP_Suite(MarChem Associates, Concord, USA). RESULTS: The within-day coefficients of variations(CVs) of most items were less than 5.0%. Ninety six percent of items showed between-day CVs less than 10.0%. All items had %relative nonlinearities less than 2.5%. The correlation coefficients of BUN, creatinine, AST, ALT, total bilirubin, direct bilirubin, gamma-GT, glucose and UA exceeded 0.975. The recovery rates were analyzed for BUN, creatinine, glucose and UA, and all were in the range of 98.2% to 102.3%. Reportable ranges were wide enough for all items. CONCLUSIONS: Linearity, precision, recovery rates and reportable ranges were satisfactory. A few CVs were relatively large due to the significant effects caused by the small differences among the measured values of low concentration specimens. Some items showed low correlation coefficients probably due to insufficient device familiarization period.
Amylases ; Bilirubin ; Cholesterol ; Chungcheongnam-do ; Creatinine ; Glucose ; Information Systems ; Korea ; Lipase ; Phosphorus ; Uric Acid

Herein, we report a case in which cholestasis caused discrepancy in high-density lipoprotein (HDL)-cholesterol levels measured using various methods. The discrepancy in HDL-cholesterol level originated from the abnormal increase in the level of an unusual lipoprotein, apo E-rich HDL, in the patient's serum. An abnormal slow alpha-migrating lipoprotein was observed on agarose gel electrophoresis, and an abnormal large-sized HDL was observed in a lipoprotein subfraction study. The level of apolipoprotein E was elevated.
Apolipoproteins ; Cholestasis ; Electrophoresis, Agar Gel ; Lipoproteins