Effects of Delayed Laboratory Processing on Platelet Serotonin Levels

Abstract

Background Despite the availability of established guidelines for measuring platelet serotonin, these guidelines may be difficult to follow in a hospital setting where time to processing may vary from sample to sample. Purpose The purpose of this study was to evaluate the effect of the time to processing of human blood samples on the stability of the enzyme-linked immunosorbent assay (ELISA) for the determination of platelet serotonin levels in human plasma. Method Human blood samples collected from a convenience sample of eight healthy volunteers were analyzed to determine platelet serotonin levels from plasma collected in ethylene diamine tetra acetic acid (EDTA) tubes and stored at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr. Results Refrigeration storage at 4°C for 3 hr, 5 hr, 8 hr, and 12 hr altered the platelet serotonin measurement when compared to immediate processing. The bias for the samples stored at 4°C for 3 hr was 102.3 (±217.39 ng/109 platelets), for 5 hr was 200.1 (±132.76 ng/109 platelets), for 8 hr was 146.9 (±221.41 ng/109 platelets), and for 12 hr was –67.6 (±349.60 ng/109 platelets). Discussion Results from this study show that accurate measurement of platelet serotonin levels is dependent on time to processing. Researchers should therefore follow a standardized laboratory guideline for obtaining immediate platelet serotonin levels after blood sample collection.

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