Serum-constituents analyses: effect of duration and temperature of storage of clotted blood.

We studied the effects on 25 analytes of duration of contact of serum with non-anticoagulated blood and of temperature. Serum was separated after blood was allowed to stand, for 0, 2, 4, 6, 8, 24, or 48 h at 4, 23, or 30 degrees C. Results obtained for bilirubin, albumin, zinc sulfate turbidity, thymol turbidity, cholinesterase (EC 3.1.1.8), alkaline phosphatase (EC 3.1.3.1), leucine aminopeptidase (EC 3.4.11.1), amylase (EC 3.2.1.2), total cholesterol, triglycerides, beta-lipoprotein, serum urea nitrogen, creatinine, uric acid, and gamma-glutamyltransferase (EC 2.3.2.2) were not influenced by storage at 4, 24, or 30 degrees C for as long as 48 h. Negligible differences were seen for potassium in sera in contact with cells as long as 24 h at 23 degrees C and for inorganic phosphorus after 48 h at 4 degrees C. However, at 4 degrees C we noted an increase at 8 h, a slight decrease at 30 degrees C. Statistically significant changes were seen for total protein and calcium after 48 h at 30 degrees C; for aspartate aminotransferase (EC 2.6.1.1), and alanine aminotransferase (EC 2.6.1.2), between 8 and 24 h at 23 degrees C and as soon as 6 h at 30 degrees C; for lactate dehydrogenase (EC 1.1.1.27) after 8 h at 30 degrees C and between 8 and 24 h at 23 degrees C; for glucose at 24, 4, or 2 h of storage at 4, 23, or 30 degrees C, respectively; for inorganic phosphorus after 48 h at 23 degrees C or 8 h at 30 degrees C; for potassium after 4 h at 4 degrees C or 24 h at 30 degrees C; and for sodium after 48 h at 4 degrees C or 6 h at 23 or 30 degrees C.