A comparative study of sample collection tubes for routine biochemical parameters.

Abstract

Background & Objectives: Turnaround time is one of the important indicators of the performance of a clinical laboratory and is the sum total of the pre-analytical, analytical and post analytical TAT. Pre-analytical TAT can be reduced by selection of appropriate sample collection tube. Our objective is to compare three such tubes for the biochemical parameters and pre-analytical TAT. Methods: Samples were collected in Plain tube, BD SST and BD heparin tubes from 50 participants and were compared for the pre-analytical TAT and seventeen biochemical parameters. Taking BD SST tube as reference, plain tube and BD lithium heparin tube were compared for the tube bias. Results: Serum LDH, AST, Potassium and phosphates were significantly higher (p=<0.05)  while serum glucose and sodium were statistically significantly (p=<0.05) lower in plain tube as compared to the BD SST and bias for these parameters was clinically significant as well. Significant difference (p=<0.05) in concentration of total protein, potassium and glucose was observed between BD SST and BD heparin tube but bias was clinically insignificant. Pre-analytical TAT was drastically reduced with use of plasma tube followed by SST and plain tube. Conclusion: We conclude that sample collection tubes contribute to the variation in the results of the biochemical parameter and TAT. During individual patient’s hospital stay samples for chemistry should always be collected into the same tube to ensure that variation in parameters are patient or disease related not tube related.