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BMC veterinary research2016; 12(1); 196; doi: 10.1186/s12917-016-0828-z

Comparison of three different methods for the quantification of equine insulin.

Abstract: Exact analysis of equine insulin in blood samples is the key element for assessing insulin resistance or insulin dysregulation in horses. However, previous studies indicated marked differences in insulin concentrations obtained from sample analyses with different immunoassays. Most assays used in veterinary medicine are originally designed for use in human diagnostics and are based on antibodies directed against human insulin, although amino acid sequences between equine and human insulin differ. Species-specific assays are being used more frequently and seem to provide advantages compared to human-specific assays. The aim of this study was to compare three immunoassays, one porcine-specific insulin enzyme-linked immunosorbent assay (ELISA), advertised to be specific for equine insulin, one porcine-specific insulin radioimmunoassay (RIA) and one human-specific insulin chemiluminescence immunoassay (CLIA), all three widely used in veterinary laboratories for the analysis of equine insulin. Furthermore, we tested their clinical applicability in assessing insulin resistance and dysregulation by analysis of basal blood and blood samples obtained during a dynamic diagnostic stimulation test (OGT) with elevated insulin concentrations. Results: Insulin values obtained from the ELISA, RIA and CLIA, investigated for analyses of basal blood samples differed significantly between all three assays. Analyses of samples obtained during dynamic diagnostic stimulation testing with consecutively higher insulin concentrations revealed significantly (p < 0.001) lower insulin concentrations supplied by the CLIA compared to the ELISA. However, values measured by ELISA were intermediate and not different to those measured by RIA. Calculated recovery upon dilution, as a marker for assay accuracy in diluted samples, was 98 ± 4 % for ELISA, 160 ± 41 % for RIA and 101 ± 11 % for CLIA. Conclusions: Our results indicate that insulin concentrations of one sample measured by different methods vary greatly and should be interpreted carefully. Consideration of the immunoassay method and reliable assay-specific reference ranges are of particular importance especially in clinical cases where small changes in insulin levels can cause false classification in terms of insulin sensitivity of horses and ponies.
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Publication Date: 2016-09-09 PubMed ID: 27613127PubMed Central: PMC5016943DOI: 10.1186/s12917-016-0828-zGoogle Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research investigates the accuracy of three widely used immunoassays for analyzing equine insulin levels to diagnose insulin resistance and dysregulation. Results indicate considerable variances in insulin concentrations measured by these methods, suggesting the need to carefully interpret findings and consider assay method and reliable assay-specific reference ranges.

Objective

This study aimed to compare the effectiveness of three commonly used immunoassays in determining equine insulin levels in blood samples. Correct analysis of equine insulin concentrations is crucial for diagnosing insulin resistance or dysregulation in horses.

Methods

The three immunoassays evaluated were:

  • A porcine-specific insulin enzyme-linked immunosorbent assay (ELISA), marketed as being specific for equine insulin.
  • A porcine-specific insulin radioimmunoassay (RIA).
  • A human-specific insulin chemiluminescence immunoassay (CLIA).

Each assay’s clinical applicability in assessing insulin resistance and dysregulation was tested through analysis of basal blood and blood samples taken during a dynamic diagnostic stimulation test (OGT) with elevated insulin levels.

Results

Significant differences were noted in insulin values obtained from the analysis of basal blood samples across the three assays. The CLIA method resulted in significantly lower insulin concentrations than ELISA when samples taken during the dynamic diagnostic stimulation testing revealed consecutively higher insulin levels. However, values measured by ELISA were not notably different from those measured by RIA.

In terms of assay accuracy in diluted samples (measured by calculated recovery upon dilution), ELISA showed 98 ± 4 %, RIA 160 ± 41 %, and CLIA 101 ± 11 % accuracy.

Conclusions

The study concluded that the insulin concentrations for a single sample measured by different methods can greatly differ. As such, results should be interpreted carefully, considering the immunoassay method used and reliable assay-specific reference ranges. This careful interpretation becomes especially crucial in clinical cases where minor changes in insulin levels can cause the misclassification of horses and ponies in terms of insulin sensitivity.

Cite This Article

APA
Warnken T, Huber K, Feige K. (2016). Comparison of three different methods for the quantification of equine insulin. BMC Vet Res, 12(1), 196. https://doi.org/10.1186/s12917-016-0828-z

Publication

BMC veterinary research
ISSN: 1746-6148
NlmUniqueID: 101249759
Country: England
Language: English
Volume: 12
Issue: 1
Pages: 196
PII: 196

Researcher Affiliations

Warnken, T
  • Department of Physiology, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173, Hannover, Germany. tobias.warnken@tiho-hannover.de.
  • Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany. tobias.warnken@tiho-hannover.de.
Huber, K
  • Institute of Animal Science, Faculty of Agricultural Sciences, University of Hohenheim, Fruwirthstraße 35, 70593, Stuttgart, Germany.
Feige, K
  • Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.

MeSH Terms

  • Animals
  • Enzyme-Linked Immunosorbent Assay / methods
  • Enzyme-Linked Immunosorbent Assay / veterinary
  • Horses / blood
  • Horses / metabolism
  • Insulin / blood
  • Luminescent Measurements / methods
  • Luminescent Measurements / veterinary
  • Radioimmunoassay / methods
  • Radioimmunoassay / veterinary
  • Reproducibility of Results
  • Sensitivity and Specificity

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