Hormone stability in human whole blood

Objective: To determine whether significant changes in the plasma concentrations of 17 hormones occur when human whole blood is held at 4 or 24degreesC for up to 24 h before separation of the plasma fraction. Design and Methods: Blood samples (EDTA) from healthy human volunteers were held at 4degreesC or 24degreesC for 0.5, 6 or 24 It before separation. Plasma concentrations of ACTH, aldosterone, gonadotrophin alpha-subunits, AVP, C-peptide, estradiol, FSH, GH, glucagon, IGF-1, IGFBP3, insulin, leptin, LH, prolactin, PTH and VIP were measured and the results compared to baseline values. Nonlinear regression was used to test for a significant mean rate of change. The time interval for median concentrations to change by 10% was determined. Results: Significant changes were observed for ACTH (decrease at 18.6 hr, 4degreesC; 17.5 hr, 24degreesC); AVP (increase at 2.6 h, 24degreesC); insulin (decrease at 16.8 hr, 4degreesC; 16.9 hr, 24degreesC) and VIP (increase at 18.6 h, 24degreesC). No changes were detected for the remaining analytes. Conclusions: The measurement of some hormones is compromised by a delay in plasma separation from normal human blood. While many hormones appear stable in normal whole blood, we recommend that processing occurs without delay. (C) 2003 The Canadian Society of Clinical Chemists. All rights reserved.