STABILITY OF VITAMIN-A, VITAMIN-C, AND VITAMIN-E, CAROTENOIDS, LIPIDS, AND TESTOSTERONE IN WHOLE-BLOOD STORED AT 4-DEGREES-C FOR 6 AND 24 HOURS BEFORE SEPARATION OF SERUM AND PLASMA

To investigate whether overnight storage causes significant changes in whole blood, we measured serum and plasma concentrations of vitamins A, C, and E, carotenoids, lipids, and testosterone in whole blood samp les stored in a refrigerator at 4 degrees C for 6 and 24 h before cent rifugation, aliquoting and freezing them at -70 degrees C or below, In comparison with baseline samples prepared within 2 h, the mean percen tage changes at 24 h were: -3.0% to +1.0% for retinol, alpha-tocophero l, and gamma-tocopherol in plasma; -8.7% to -0.1% for carotenoids in p lasma; -7.2% for vitamin C in plasma and -1.8% for vitamin C in serum; -2.7% to +2.4% for lipids in serum; and +0.4% to +6.2% for testostero ne in serum and plasma from men and women, Spearman's rank correlation coefficients between measurements made in the baseline samples and th ose made after storage for 24 h were greater than 0.9 for 11 analytes, between 0.8 and 0.9 for 7 analytes, and less than 0.8 for only 1 anal yte (vitamin C in serum), The ratio of between-subject to within-subje ct coefficients of variation was greater than 3.0 for all analytes exc ept lutein (ratio, 1.6), alpha-cryptoxanthin (ratio, 2.4) and vitamin C (ratio in serum, 3.0; ratio in plasma, 2.2), We conclude that storag e of whole blood at 4 degrees C for 24 h before freezing does not caus e important changes in the analytes studied and that this delay in pro cessing may be incorporated in the design of large prospective studies .