The Effect of Lipemia on Insulin and Adiponectin Measurement in Equine Blood Samples.
Abstract: Lipemia is a common comorbidity in horses with obesity or equine metabolic syndrome, but the impact of lipemia on the measurement of insulin and adiponectin has not been evaluated. Objective: To evaluate endogenous and exogenous lipemic interference with equine insulin and adiponectin measurements via several commercial assays. Methods: Endogenous lipemia was evaluated using plasma and serum samples with triglyceride concentrations of 1000 mg/dL (n = 6 each). Sample insulin concentrations were determined via fluorescence enzyme immunoassay (FEIA), ELISA, and lateral flow assay (LFA). Test agreement was assessed using Pearson's correlation coefficient, Passing-Bablok regression, and Bland-Altman analysis. Exogenous lipemia was evaluated using pools of serum, plasma, and whole blood (n = 5 each) spiked with Intralipid 20% to triglyceride concentrations of 0, 50, 100, 250, 500, and 1000 mg/dL. Insulin concentrations were measured via FEIA, ELISA, and LFA, and adiponectin concentrations via immunoturbidometric assay (ITA). Interferograms were created and a Kruskal-Wallis test was used to compare bias between triglyceride concentrations. Results: With endogenous lipemia, agreement between the three assays was excellent (r > 0.90) with no appreciable impact of triglyceride concentration. For exogenous lipemia, significant (p < 0.05) negative interference was observed at triglyceride concentrations of 1000 mg/dL with the insulin ELISA using plasma. No significant interference was found for the insulin ELISA or FEIA using serum, insulin LFA using whole blood or plasma, or adiponectin ITA using serum. Conclusions: Falsely low insulin values may be obtained at high triglyceride concentrations with the insulin ELISA using plasma.
© 2026 The Author(s). Veterinary Clinical Pathology published by Wiley Periodicals LLC on behalf of American Society for Veterinary Clinical Pathology.
Publication Date: 2026-02-16 PubMed ID: 41699877DOI: 10.1111/vcp.70100Google Scholar: Lookup
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- Journal Article
Summary
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Overview
- This study investigates how lipemia (high blood fat levels) affects the accuracy of insulin and adiponectin measurements in horses, particularly those with metabolic issues.
- The research compares different assay methods to see if lipemia causes false readings in blood tests commonly used for diagnosing equine metabolic syndrome.
Background and Purpose
- Lipemia, characterized by elevated triglycerides in the blood, frequently occurs in horses with obesity or equine metabolic syndrome (EMS).
- Accurate measurement of insulin and adiponectin is critical for diagnosing and monitoring EMS, but the impact of lipemia on these measurements was unclear prior to this study.
- The study aimed to evaluate both endogenous (naturally occurring) and exogenous (artificially added) lipemia interference on insulin and adiponectin assays.
Methods
- Samples: Blood samples were collected from horses, including:
- Plasma and serum samples with endogenous triglyceride concentrations >1000 mg/dL (6 samples each).
- Pools of serum, plasma, and whole blood (5 samples each) artificially spiked with Intralipid 20% to adjust triglyceride levels from 0 to 1000 mg/dL.
- Assays used:
- Insulin was measured by:
- Fluorescence enzyme immunoassay (FEIA)
- ELISA (enzyme-linked immunosorbent assay)
- Lateral flow assay (LFA)
- Adiponectin was measured via immunoturbidometric assay (ITA).
- Insulin was measured by:
- Data Analysis:
- Agreement between assays was assessed with Pearson’s correlation, Passing-Bablok regression, and Bland-Altman analysis.
- Effects of varying triglyceride concentrations (especially at 1000 mg/dL) were evaluated with interferograms and the non-parametric Kruskal-Wallis test to determine bias.
Results
- Endogenous Lipemia:
- High triglyceride blood samples showed excellent agreement between all three insulin assays (correlation coefficient r > 0.90).
- No significant effect of naturally high triglycerides on insulin or adiponectin measurements was observed.
- Exogenous Lipemia:
- When triglyceride concentrations were artificially increased, a significant negative interference was detected only with the insulin ELISA in plasma samples at 1000 mg/dL triglycerides (p < 0.05).
- No significant interference was seen with:
- Insulin ELISA or FEIA using serum samples.
- Insulin LFA using whole blood or plasma.
- Adiponectin ITA using serum.
Conclusions and Implications
- Lipemia generally does not interfere with the accuracy of insulin and adiponectin assays in horses under typical clinical conditions.
- However, extremely high triglyceride levels (≥1000 mg/dL) can cause falsely low insulin readings specifically when using the insulin ELISA on plasma samples.
- Clinicians should be cautious interpreting low insulin results from plasma ELISA tests in lipemic horses, considering alternative assay methods or sample types.
- Using serum samples or other assays like FEIA or LFA may reduce the risk of lipemia-related measurement errors.
Summary
- This study provides important guidance to veterinarians on the reliability of insulin and adiponectin tests for horses with lipemia, ensuring better diagnostics and management of equine metabolic problems.
- It encourages awareness of assay-specific limitations and supports using appropriate methods to avoid diagnostic errors due to blood fat interference.
Cite This Article
APA
Hallowell KL, van Eps AW, Kulp JC, Schnabel LV.
(2026).
The Effect of Lipemia on Insulin and Adiponectin Measurement in Equine Blood Samples.
Vet Clin Pathol.
https://doi.org/10.1111/vcp.70100 Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
- Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.
- Department of Clinical Studies, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania, USA.
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
- Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina, USA.
Grant Funding
- Laminitis Research Fund, University of Pennsylvania
- T32OD011130 / NIH HHS
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