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

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

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

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

No abstract available.
*Algorithms ; Automation ; Clinical Laboratory Information Systems/*standards ; Humans ; Immunoassay/*methods ; Indicator Dilution Techniques ; alpha-Fetoproteins/*analysis

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

INTRODUCTION: Hypomagnesemia, major cause of hypocalcemia, is developed due to insufficient oral intake in hospitalized patient and high prevalence in intensive care unit (ICU) patient. It is important to monitoring ionized magnesium in ICU patient because hypomagnesemia has been implicated in the development of cardiovascular dysfunction. So, in this study we determine the relation between ionized calcium and ionized magnesium and validate the measurement of ionized magnesium. MATERIAL AND METHOD: From March 2005 to may 2005, total 2876 samples were enrolled, which was requested to measure ionized calcium. We measured ionized calcium and ionized magnesium using NOVA CCX (Nova Biomedical, Waltman, MA, USA). Reference range of ionized calcium and ionized magnesium was 3.9~4.5 and 1.1~1.5 mg/dL, respectively. The patients were grouped as adult above 18 years old and pediatric below 18 years old. The ward was intensive care unit (ICU), general ward, outpatient and emergency room. We investigate the frequency of hypocalcemia and hypomagnesemia. RESULTS: The prevalence of ionized hypocalcemia (Ca2+ < 3.9mg/dL) was 22.2% and the prevalence of ionized hypomagnesemia (Mg2+ < 1.1mg/dL) was 41.9%. Of 2876 samples, 377 samples had ionized hypocalcemia and ionized hypomagnesemia simultaneously. Fifty-nine percent samples showing ionized hypocalcemia had ionized hypomagnesemia. In pediatric patients 13.3% of all patients had ionized hypocalcemia, 20.0% showing ionized hypercalcemia and 37.6% showing ionized hypomagnesemia. In adult patients 24.3% of all patients had ionized hypocalcemia, 14.3% showing ionized hypercalcemia, 48.2% showing ionized hypomagnesemia and one patient had ionized hypermagnesemia. When considering total cases of ionized calcium, the average level of ionized calcium was lowest in emergency room. When considering in case of patients, ICU showed the lowest level of ionized calcium. CONCLUSION: Ionized hypomagnesemia had known to be one of the major causes of ionized hypocalcemia and is common in ionized hypocalcemia. It is easy to found by measuring simultaneously. We found high coincidence rate of ionized hypocalcemia and ionized hypomagnesemia. We recommend that all samples ordered to be measuring ionized calcium must be checked ionized magnesium simultaneously.
Adolescent ; Adult ; Calcium ; Emergency Service, Hospital ; Humans ; Hypercalcemia ; Hypocalcemia* ; Intensive Care Units ; Magnesium ; Outpatients ; Patients' Rooms ; Prevalence ; Reference Values

BACKGROUND: We aimed to assess the performance of the five creatinine-based equations commonly used for estimates of the glomerular filtration rate (eGFR), namely, the creatinine-based Chronic Kidney Disease Epidemiology Collaboration (CKD-EPIcr), Asian CKD-EPI, revised Lund–Malmö (revised LM), full age spectrum (FAS), and Korean FAS equations, in the Korean population. METHODS: A total of 1,312 patients, aged 20 yr and above who underwent ⁵¹Cr-EDTA GFR measurements (mGFR), were enrolled. The bias (eGFR–mGFR) and precision (root mean square error [RMSE]) were calculated. The accuracy (P30) of four eGFR equations was compared to that of the CKD-EPIcr equation. P30 was defined as the percentage of patients whose eGFR was within±30% of the mGFR. RESULTS: The mean bias (mL·min⁻¹·1.73 m⁻²) of the five eGFR equation was as follows: CKD-EPIcr, -0.6; Asian CKD-EPI, 2.7; revised LM, -6.5; FAS, -2.5; and Korean FAS, -0.2. The bias of the Asian CKD-EPI, revised LM, and FAS equations showed a significant difference from zero (P<0.001). The RMSE values were as follows: CKD-EPIcr, 15.6; Asian CKD-EPI, 15.6; revised LM, 17.9; FAS, 16.3; and Korean FAS, 15.8. There were no significant differences in the P30 except for the Asian CKD-EPI equation: CKD-EPIcr, 76.6%; Asian CKD-EPI, 74.7%; revised LM, 75.8%; FAS, 76.0%; and Korean FAS, 75.8%. CONCLUSIONS: The CKD-EPIcr and Korean FAS equations showed equivalent analytical and clinical performances in the Korean adult population.
Adult* ; Asian Continental Ancestry Group ; Bias (Epidemiology) ; Cooperative Behavior ; Creatinine ; Epidemiology ; Glomerular Filtration Rate* ; Humans ; Renal Insufficiency, Chronic

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

BACKGROUND: The previous performance tests of URiSCAN GEN 10SGL dipstick reagent strip (Yeongdong pharmaceutical Co., Seoul, Korea) were mainly done by comparison with the approved urine strips. However, adequate comparison was inavailable because the grading systems were different among the manufacturers. We evaluated the correlation of new generation URiSCAN GEN 10SGL urine strip with known quantitative, microscopic, and culture methods. METHODS: We used urine specimens which were collected for the urinalysis and culture from November 2000 to Mars 2001. We evaluated the correlation between the results of URiSCAN GEN 10SGL and the quantitative methods by comparing the mean of change of reflectance rate (change %R) with the result of the corresponding quantitative method for protein, glucose, bilirubin, urobilinogen, pH, and specific gravity. To calculate the sensitivity and specificity, we used microscopic examination for leukocytes and erythrocytes, and used urine culture for nitrite test. RESULTS: The correlation coefficients between the change %R of URiSCAN GEN 10SGL and the corresponding quantitative method exceeded 0.81, except bilirubin and specific gravity (P<0.01; respectively). The agreements of identical or neighboring concentration block were more than 90%, except urobilinogen and specific gravy. The sensitivity and specificity of URiSCAN GEN 10SGL were 63.6% and 94.2% for leukocytes; 92.8% and 74.1% for erythrocytes; 74.4% and 85.0% for nitrite producing organisms. CONCLUSTIONS: URiSCAN GEN 10SGL had acceptable accuracy and agreement compared with the corresponding quantitative methods and culture result. Also, it had improved sensitivity and specificity of leukocytes and erythrocytes detection compared with previous URiSCAN urine dipstick strip.
Bilirubin ; Erythrocytes ; Glucose ; Hydrogen-Ion Concentration ; Leukocytes ; Mars ; Reagent Strips ; Sensitivity and Specificity ; Seoul ; Specific Gravity ; Urinalysis ; Urobilinogen