Evaluation of quality indicators in pre-analytical phase of testing in clinical biochemistry laboratory of a tertiary care hospital in India

Abstract

Preanalytical errors account for nearly 70% of the total number of laboratory errors. Hence, controlling them is a big challenge. Quality Indicators expressed as sigma metrics provide a convenient way to objectively quantify errors. Aim: To quantify performance in the preanalytical phase of the testing process in Clinical Biochemistry laboratory of a tertiary care hospital in India using quality indicators. Study period: January to September 2016. Quality Indicators (QIs) used: samples lost–not received (QI-8); samples collected in an inappropriate blood collection tube (QI-9); haemolyzed samples (QI-10); clotted samples (QI-11); samples with insufficient sample volume (QI-12); improperly labelled (QI-15); damaged in transport (QI-14). Sigma metric was calculated for the above mentioned QIs. The total number of samples received during the study period was 5,73,694 and the total number of preanalytical errors was 1,782. Among the preanalytical errors, 43.9% were samples with insufficient volume (sigma: 4.5), 33.2 % were haemolyzed samples (sigma: 4.6), 11.3% were samples collected in an inappropriate blood collection tube (sigma: 4.9), 6.7% were samples not received in the laboratory (sigma: 5.1), 4.2% were clotted samples (sigma: 5.2), 0.7% were improperly labelled (sigma: 5.6), only one sample (0.06%) was lost over 9 months period due to spill in pneumatic chute. QIs serve as a tool to monitor process performance in the laboratory. In this study, insufficient sample volume and haemolysis were the major causes of preanalytical errors. All QIs had acceptable sigma value. Regular training of phlebotomists regarding the preanalytical errors needs to be conducted to achieve six sigma performance.