Stability study of 81 analytes in human whole blood, in serum and in plasma

Objective: We studied the pre-analytical stability of 81 analytes based on the variables of delay before processing, storage as whole blood or serum/plasma, the storage temperature and the type of tube the sample was stored in.

Design and methods: The mean difference between assays for samples from 10 subjects was calculated with the samples being kept under different storage conditions and for different times between sampling time and analysis: up to 24h for biochemistry, coagulation and hematology, and up to 72 h for hormonology. This difference was compared to the acceptable limits derived from the analytical and the intra individual biological variation.

Results: Most of the analytes investigated remained stable up to 24h under all storage conditions prior to centrifugation. However, some analytes were significantly affected either by delay, tube type or temperature, such as potassium, inorganic phosphorus, magnesium, LD, glucose, lactate, mean corpuscular volume, mean corpuscular hemoglobin, activated partial thromboplastin time, insulin, C-peptide, PTH, osteocalcin, C-telopeptide and ACTH.

Conclusion: This study may be useful to help define acceptable delay times and storage conditions when a short time between sample collection and processing is not possible.