Haemolysis affects insulin but not C-peptide immunoassay.
Author(s): O'Rahilly S, Burnett MA, Smith RF, Darley JH, Turner RC
Publication: Diabetologia, 1987, Vol. 30, Page 394-6
PubMed ID: 3315796 PubMed Review Paper? No
Purpose of Paper
The purpose of this paper was to determine the effects of hemolysis and method of insulin separation on the measurement of insulin and c-peptide in plasma.
Conclusion of Paper
Measured insulin levels declined with increasing plasma hemoglobin levels, regardless of which assay was used to quantify the insulin. Generally, traumatized specimens with no visible hemolysis had insulin levels comparable to non-traumatized specimens, but 2 of the 19 specimens had reduced insulin levels. In contrast, plasma c-peptide levels were unaffected by hemolysis. Strong correlations were observed between insulin levels measured after different methods of insulin separation, but higher levels were measured after double-antibody rather than charcoal separation (15.1 versus 9.0 mU/L).
Studies
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Study Purpose
The purpose of this study was to determine the effects of hemolysis and method of insulin separation on the measurement of insulin and c-peptide in plasma. Four lithium-heparin blood specimens were obtained from each of 19 fasting relatives of type 2 diabetes patients 2 h after the start of glucose infusion into the bloodstream. Specimens were hemolyzed by passage through a 23 gauge needle 0, 2, 3, or 4 times, after which plasma was obtained and stored at -20°C.
Summary of Findings:
Measured insulin levels declined with increasing plasma hemoglobin levels and hemolysis score, regardless of which assay was used to quantify the insulin. Generally, hemolyzed specimens with no visible hemolysis had insulin levels comparable to non-traumatized specimens, but 2 of the 19 specimens had reduced levels. In contrast, plasma c-peptide levels were unaffected by hemolysis. The insulin levels measured by the assays with different methods of insulin separation were strongly correlated (r2=0.76), but insulin was higher when separation was performed by the double-antibody rather than by the charcoal method (15.1 versus 9.0 mU/L).
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Radioimmunoassay Peptide Radioimmunoassay Protein Macroscopic observation Protein Immunoassay Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Analyte Extraction and Purification Analyte isolation method Charcoal separation
Double-antibody separation
Biospecimen Aliquots and Components Hemolysis Fine needle aspiration-induced
Not induced