High stability of markers of cardiovascular risk in blood samples.

Abstract

Biomarkers representing long-term risk of coronary heart disease are widely used in epidemiologic research. Procedures for blood sampling and processing need to be efficient and cost-effective to enable large sample sizes for greater statistical power and precision. Transfer of blood samples by mail is less expensive, easier to perform, and less time-consuming than fast courier services or asking patients to attend a central laboratory for blood sampling. This approach may be incorporated into routine practice and may reduce the likelihood of missing data and random error (1)(2) and eliminate intercenter variability. Although the stabilities of many analytes at different temperatures and different time intervals have been reported (3)(4)(5)(6)(7) and some studies have mimicked transportation conditions (2)(8), to our knowledge neither the effects of transfer by a next-working-day mail service nor the effects on the fatty acid (FA) composition are known. We therefore investigated the variability and reliability of risk factors for coronary heart disease in blood samples delivered by a next-working-day mail service, which is available within most Western countries. We studied 20 healthy volunteers (7 men and 13 women) working at our department, with a mean age of 39 years (range, 23–54 years) and a mean (SD) body mass index of 23.7 (4.8) kg/m2. The study was approved by the Medical Ethical Review Committee of Wageningen University, and written informed consent was obtained from all participants. One set of three tubes of blood was collected in the morning by one trained phlebotomist from each of eight volunteers after an overnight fast: a 10-mL tube containing 18 mg of EDTA, a 4.0-mL tube containing 8 mg of potassium oxalate and 10 mg of sodium fluoride (as antiglycolytic agents), and a 9.5-mL serum separator (SST) tube (Becton …