Phoenix in the lab: The sigma metrics during Chennai’s worst disaster: Monitoring and management of the Quality Management System (QMS)

Srinivas Chakravarthy, Satish Ramanathan, Smitha S, Vijayakumar KV, Thirumalai Nallathambi, Micheal S


Background: Sigma is a quality management tool that helps in continuous monitoring and improvement of the performance of the analytes in the clinical laboratory. The present study evaluated the performance of our Quality Management System under optimal condition as well as during the adverse condition due to unexpected flooding in Chennai, India in the month of December 2015.

Methods: The performance of the assays in the clinical laboratory was evaluated in sigma scale for 27 routine analytes under optimal condition, adverse condition during the disaster, and after restoring the optimal condition.

Results: The performance of each analyte was analyzed to evaluate the quality of results released under all the three situations viz., optimal condition (Pre-disaster phase); adverse condition (Disaster phase) and after re-establishing the optimal condition (Post-disaster phase). Six analytes showed poor performance with a sigma <3 during the adverse condition at level 1 control and 5 analytes for level 2 control showed sigma <3. After re-establishing the optimal condition, 4 analytes showed an acceptable performance of >3 sigma. Alanine aminotransferase showed a <3 sigma performance at level 1 control and bicarbonate at both levels of quality control even after the optimal condition was restored.

Conclusion: Even in adverse condition, the quality of the results released from VITROS 5600 integrated system was not much impacted except for a few analytes.  Analysis using quality goal index (QGI) showed that imprecision was the reason behind the unacceptable sigma. Good clinical laboratory practices aided us in improving the quality of performance of these analytes.


Chakravarthy S, Ramanathan S, Smitha S, Vijayakumar KV, Nallathambi T, Michael S. IJPLM. 2017;3(1):OA1


Imprecision, Bias, Disaster management, sigma, QGI, TE


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