ABSTRACT
BACKGROUND: Comparison of assay results is very important for having a comparable backup analyzer to provide a quality laboratory service without interruption. Even though, several factors affect assay results by different instruments, little or no data is available regarding assay results comparison between Cobas 6000 (c501) and Cobas integra 400 plus in the study area. Thus, the present study was aimed to compare assay results of two fully auto-mated clinical chemistry analyzers: Cobas 6000 (c501) and Cobas Integra 400 Plus at the National Clinical Chemistry Reference Laboratory of Ethiopian Public Health Institute, Addis Ababa, Ethiopia. METHODS: The assay results for the 20 selected clinical chemistry parameters were obtained from 52 randomly selected samples on Cobas 6000 (c501) and Cobas integra 400 plus. Statistical analysis was done using Med-Calc software. The 2019 CLIA proposed acceptance limits for proficiency testing were used to check bias or difference obtained from correlation and regression analysis. RESULTS: Assay results comparison revealed almost perfect data correlations among all selected clinical chemistry parameters: Albumin, ALP, ALT, Alpha-amylase (AMYL), AST, Direct bilirubin, Total bilirubin, Total cholesterol, Creatine kinase, Creatine kinase MB-subunit, Creatinine, GGT, Glucose, HDLC4, LDH, Phosphate, Total Protein, Triglycerides, Uric acid, and Urea, on both analyzers with coefficient of determination (R2) ranging from 98.9% to 99.99% and coefficient of correlation (r) ranging from 99.4% to 100%, depicting the precision and reliability of assay results, standardization, and system equivalency. Moreover, the calculated bias/difference is lower than both CLIA total allowable error and CLIA allowable error. CONCLUSIONS: In summary, regression/correlation analysis and calculated bias or difference revealed almost equivalent data representation of both analyzers as per the CLIA standard, thus showing that both fully automated analyzers are standardized and properly calibrated to be used simultaneously and inter-changeably as the main and back up analyzers for selected clinical chemistry parameters analyzed at the clinical chemistry reference laboratory.
Subject(s)
Bilirubin , Chemistry, Clinical , Ethiopia , Humans , Reference Standards , Reproducibility of ResultsABSTRACT
Clinical laboratories are mandated to deliver accurate, reliable, timely and correctly reported result which, used in decision making for disease screening, diagnosis and monitoring. With aid of six sigma principles and metrics it is possible to assess the quality laboratory process and the quality control that is needed to ensure that the desired quality is achieved. Thus, this study was undertaken to evaluate the performance of biochemical parameters by calculating the sigma metrics of individual parameters using internal quality control (IQC) and Proficiency Testing (PT) results. The sigma metrics of 21 clinical chemistry parameters were calculated from COBAS 6000 analyzer with internal quality control (IQC) materials and external quality assurance scheme (EQAS) performance in national clinical chemistry laboratory for the period of six months. We obtained an excellent performance (≥ 6 sigma) for test parameters amylase pancreatic, amylase total, HDL, magnesium, AST, triglyceride, total bilirubin and ALT in both levels of quality control. Urea, creatinine and chloride were failed to meet the minimal sigma performance for both level 1 and 2. Sigma values of 3-6 were observed for ALP, Direct bilirubin, total protein, albumin, glucose, potassium, and phosphate with both levels of quality control. Though, stringent IQC strategy is not mandatory for analytes that scored sigma value ≥ 6. However, continuous monitoring quality control is required for renal function tests and process improvement will be designed for those with poor sigma values.
ABSTRACT
Background: Even though several factors affect reference intervals (RIs), company-derived values are currently in use in many laboratories worldwide. However, few or no data are available regarding serum proteins RIs, especially in resource-limited countries such as Ethiopia. Objective: To establish RIs for serum protein electrophoresis of apparently healthy adults in Addis Ababa, Ethiopia. Methods: A cross-sectional study was conducted on a total of 297 apparently healthy adults from April to October 2019 in four selected sub-cities (Akaki, Kirkos, Arada, and Yeka) of Addis Ababa, Ethiopia. Laboratory analysis of collected samples was performed using the Capillarys 2 Flex Piercing analyzer, while statistical analysis was conducted using SPSS version 23 and Med-Calc software. The Mann-Whitney test was used to check partitions. A non-parametric method of reference range establishment was performed as per CLSI guideline EP28A3C. Results: The established RIs were: albumin 53.83-64.59%, 52.24-63.55%; alpha-1 globulin 3.04-5.40%, 3.44-5.60%; alpha-2 globulin 8.0-12.67%, 8.44-12.87%; and beta-1 globulin 5.01-7.38%, 5.14-7.86%. Moreover, the albumin to globulin ratios were 1.16-1.8 and 1.09-1.74 for males and females, respectively. The combined RIs for beta-2 globulin and gamma globulin were 2.54-4.90% and 12.40-21.66%, respectively. Conclusion: The established reference interval for serum protein fractions revealed gender-specific differences, except for beta-2 globulin and gamma globulin.