Effect of anticoagulants and storage temperatures on stability of plasma and serum hormones

Objectives: To determine the effect of different anticoagulants and storage conditions on the stability of hormones in plasma and serum. Design and methods: Human blood samples were collected from volunteers into EDTA, lithium heparin, sodium fluoride/potassium oxalate, or tubes without anticoagulant, plasma and serum left at −20°C, 4°C or 30°C for 24 and 120 hours then assayed for ACTH, aldosterone, α-subunit, AVP, CRH, C-peptide, estradiol, FSH, glucagon, GH, IGF-1, IGFBP-3, insulin, leptin, LH, PPP, PTH, prolactin and VIP, or at room temperature for 0 to 72 hours (BNP, NT-BNP)(n = 6 per condition). Results: The anticoagulant altered the measured concentrations for 9 hormones when compared to EDTA. All hormones except ACTH were stable for >120 hours in EDTA or fluoride at 4°C, but only 13 hormones were stable in all anticoagulants. At 30°C, 8 hormones were stable for >120 hours in EDTA, and 3 hormones in all anticoagulants. BNP and NT-BNP were stable for <24 hours when stored in EDTA or heparin at room temperature. Discussion: Storage of samples in EDTA plasma at 4°C is suitable for most hormones (except ACTH) for up to 120 hours