Abstract :
Introduction and Aims: Clinical laboratories are backbone of health care system & the responsibility lies
in the laboratory to produce reliable, reproducible & timely interpreted test results. Presently Westgard
quality control(QC) rules are the basis for quality control validation of laboratories. A new quality
assessment system known as Six sigma is considered as world class quality & is a uniquely defined scale
with which one can assess the performance of a laboratory. An analytical procedure should achieve a good
sigma levels for high reliability for the results. Many laboratories are not aware about the usefulness of six
sigma. Hence this study was aimed to assess and to plan the quality control strategy.
Materials and Methods: In this study, the internal quality control data of urea, creatinine, sodium,
potassium & chloride analysed for a period of 6 months & used to calculate bias, coefficient of variation
(CV)%, mean & standard deviation(SD) for each levels(L1,L2).
Results: Sigma value calculated shown Highest for Urea & Potassium (Level1 & Level 2) COBAS 6000
an integrated modular analyser. Sigma of 3 is the minimum acceptable level of quality. The frequency of
internal QC should be increased and corrective action should be taken for those parameters with sigma
Sigma metrics of each parameter helped us to identify the right QC strategy for that analyte using Westgard
sigma rule.
Conclusion: Hence six sigma is a more efficient way to control quality & is a self-assessment tool for
quality improvement.
Keyword :
Quality control, Six sigma, Standard deviation (SD), Total allowable error.