Stability of routine biochemical analytes in whole blood and plasma/serum: focus on potassium stability from lithium heparin.
Author(s): Dupuy AM, Cristol JP, Vincent B, Bargnoux AS, Mendes M, Philibert P, Klouche K, Badiou S
Publication: Clin Chem Lab Med, 2018, Vol. 56, Page 413-421
PubMed ID: 28888086 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of delayed blood processing and delayed analysis on levels of 23 clinical chemistry analytes in plasma and nine analytes in serum.
Conclusion of Paper
Storage of blood for up to 24 h before centrifugation affected only the measurement of potassium (by 8 h), bicarbonate (by 12 h), lactate dehydrogenase (LDH, by 12 h), and magnesium (by 24 h) in plasma and C-peptide, osteocalcin, and parathyroid hormone (PTH) in serum. Post-centrifugation storage of plasma in the collection tube affected the measurement of LDH, bicarbonate, potassium, phosphorous, and aspartate aminotransferase (AST) in plasma and post-centrifugation storage of serum significantly affected levels of osteocalcin and PTH.
Studies
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Study Purpose
This study investigated the effects of delayed blood processing and delayed analysis on levels of 23 clinical chemistry analytes in plasma. Blood was collected from six healthy patients and four patients in the intensive care units into seven Vacuette lithium heparin tubes. Plasma was obtained by centrifugation of blood at 2000 x g for 10 min both immediately (0 h) and after 2, 4, 6, 8, or 24 h at room temperature with inversion every 20 min. Specimens were analyzed immediately after centrifugation and again after 2, 4, 6, 8, 12, 24, and 48 h at 4˚C. Levels of bicarbonate, ferritin, LDH, magnesium, NT-proBNP, phosphorus, potassium, total bilirubin, high-sensitivity troponin T, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, urea, calcium, chloride, creatine kinase, creatinine, C-reactive protein, gamma-glutamyl transferase, lipase, myoglobin, sodium, and uric acid were determined using a Cobas 8000 system. Instability was defined as deviation greater than the total change limit as defined in a previous publication.
Summary of Findings:
Storage of blood at room temperature prior to centrifugation resulted in unacceptable changes in levels of potassium after 8 h (-6.5%), bicarbonate (-8.8%) and LDH (12.6%) after 12 h, and magnesium after 24 h (7.7%). All other analytes in plasma remained stable when blood was stored for up to 24 h before centrifugation. Post-centrifugation storage of plasma in the collection tube resulted in significant changes in LDH after 2 h (11.5%), bicarbonate after 4 h (-11.3%), and potassium and phosphorous after 24 h (9.6% and 7.7%, respectively). Levels of AST increased 14.7% when stored for 48 h post-centrifugation, but stability was unclear as earlier time-points weren’t tested. All other analytes remained unchanged after a refrigerated storage for 48 h in the centrifugation tube.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Other diagnoses
- Normal
Platform:
Analyte Technology Platform Electrolyte/Metal Clinical chemistry/auto analyzer Protein Clinical chemistry/auto analyzer Peptide Clinical chemistry/auto analyzer Small molecule Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Time at room temperature 0 h
2 h
4 h
6 h
8 h
12 h
24 h
Biospecimen Aliquots and Components Centrifugation Centrifugation delays investigated
Storage Storage duration 0 h
2 h
4 h
6 h
8 h
12 h
24 h
48 h
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Study Purpose
This study investigated the effects of delayed blood processing and delayed analysis on levels of nine clinical chemistry analytes in serum. Blood was collected from six healthy patients and four patients in the intensive care units into seven Vacutainer tubes. Serum was obtained by centrifugation of blood at 2000 x g for 10 min after allowing for clotting (30 min) and after 2 h, 4 h, 6 h, or 24 h at room temperature with inversion every 20 min. Specimens were analyzed immediately after centrifugation and again after 2, 4, 6, 8, 12, 24, and 48 h at 4˚C. Levels of apolipoprotein A1, apolipoprotein B, cholesterol, HDL cholesterol, triglycerides, C-peptide, insulin, osteocalcin, and parathyroid hormone (PTH) were determined using a Cobas 8000 system. Not all analytes were measured at each time-point. Instability was defined as deviation greater than the total change limit as defined in a previous publication.
Summary of Findings:
Levels of all analytes in serum were stable when centrifugation was delayed for up to 6 h, but unacceptable changes in levels of C-peptide (-23.4%), osteocalcin (-33.5%), and PTH (-36.2%) occurred when centrifugation was delayed by 24 h in. All other analytes in serum remained stable when blood was stored for up to 24 h before centrifugation. While none of the reported changes with post-centrifugation storage exceeded the total change limit, the authors report that osteocalcin was only stable until 6 h and PTH to 24 h (longer time-points not tested).
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Other diagnoses
- Normal
Platform:
Analyte Technology Platform Steroid Clinical chemistry/auto analyzer Peptide Clinical chemistry/auto analyzer Protein Clinical chemistry/auto analyzer Lipid Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Aliquots and Components Centrifugation Centrifugation delays investigated
Storage Storage duration 0 h
2 h
4 h
6 h
12 h
24 h
48 h
Storage Time at room temperature 30 min
2 h
4 h
6 h
24 h