Comparison of three different methods for the quantification of equine insulin.
Authors: Warnken T, Huber K, Feige K
Journal: BMC veterinary research
Summary
# Editorial Summary: Equine Insulin Quantification Methods Accurate measurement of circulating insulin is fundamental to diagnosing insulin resistance and dysregulation in horses, yet the immunoassays commonly employed in veterinary laboratories show concerning variability in their results. Warnken and colleagues compared three widely-used assays—a porcine-specific ELISA marketed for equine use, a porcine-specific RIA, and a human-specific CLIA—by analysing paired blood samples from horses at rest and during oral glucose tolerance testing to assess their performance across basal and elevated insulin concentrations. The researchers found substantial discrepancies between assay results, with marked differences in absolute insulin values and in the classification of horses as insulin dysregulated or resistant depending on which method was used. These findings have immediate practice implications: the assay selected significantly influences diagnostic outcomes and treatment decisions, meaning practitioners should understand which method their laboratory employs and, ideally, use consistent assays for serial monitoring of individual horses. Standardisation of equine insulin measurement and careful interpretation of results in the context of the specific assay platform remain essential until species-specific assays with superior analytical concordance become universally available.
Read the full abstract on PubMed
Practical Takeaways
- •Know which insulin assay your laboratory uses—results are not interchangeable between assays, and clinical reference ranges must match the specific assay method
- •When diagnosing insulin resistance or dysregulation, ensure your diagnostic criteria (basal values, response to oral glucose tolerance test) align with the assay used by your lab
- •Request species-specific assays when possible, as porcine-specific assays appear more reliable for equine samples than human-specific assays
Key Findings
- •Significant differences in insulin concentrations were found between the three immunoassays (porcine-specific ELISA, porcine-specific RIA, and human-specific CLIA)
- •Species-specific assays showed improved accuracy compared to human-specific assays for equine insulin measurement
- •Assay selection substantially affects interpretation of basal and stimulated insulin values in diagnostic testing