First assessment the analytical quality specification in Clinical Chemistry laboratory, using Sigma scale and EQA/PT in Iran: a pilot study

Abstract

Background: To assess the analytical performance of quality trough external quality assesses and internal quality program data on sigma scale.

Method and material: Imprecision was determined from the cumulative Levey-jenning SD over the 6 month, bias was calculated from the external quality records, Finally, analytical sigma metric estimates were calculated for each Analytes by the following equation: sigma metric: (TEa – Bias)/CV. All function and statistical analysis were done in our Private laboratories.

Result: The sigma value >6 was observed for most analytes. Some of analytes have poor sigma metric <3 such as Creatinine and ALP in normal level and Calcium in pathologic level. Glucose, Urea, Uric Acid, Calcium, Phosphorous, total bilirubin, in normal levels and Urea, Creatinine, total and direct bilirubin in pathologic level have intermediate sigma metric 4-6.

Conclusion: Chemistry tests are not commodities. Quality varies significantly from manufactures to manufactures and method to method. The sigma-assessment from multiple EQA/IQC programs provides more insight into the performance of methods and quality. Laboratory seeking optimal quality program would do well to consult this data as part of their decision-working process.