Stability of analytes related to clinical chemistry and bone metabolism in blood specimens after delayed processing.

OBJECTIVES: We investigated the stability of 36 analytes related to clinical chemistry in a controlled storage study. DESIGN AND METHODS: Blood was collected from 11 subjects and was maintained for 45 min, 2.5 h, 5 h, or 24 h after phlebotomy before centrifugation. RESULTS: Statistically significant changes were observed only for parathyroid hormone, osteocalcin, zinc, pyridoxal 5'-phosphate, and homocysteine. CONCLUSIONS: These studies indicate that many analytes in clinical chemistry are stable for 24 h before centrifugation.