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Home / Equine Research Bank / J Equine Vet Sci / Changes in equine complete blood count parameters and inflam...
Journal of equine veterinary science2025; 155; 105705; doi: 10.1016/j.jevs.2025.105705

Changes in equine complete blood count parameters and inflammatory indices with inflammation.

Abstract: Early detection of inflammation using a common test could be a valuable tool for preserving horse health. Objective: This observational study aimed to identify variation in complete blood count (CBC) parameters and inflammatory indices with inflammation, and to develop reference intervals (RIs) from horses with known inflammatory states, hypothesizing that RIs developed from horses with normal acute phase protein concentrations would improve the ability to predict inflammation. Methods: Concentrations of serum amyloid A (SAA) and haptoglobin from clinically healthy horses and horses under veterinary care (n=199) were used to categorize horses as inflamed (SH+; n=48) or not inflamed (SH-; n=150). Non-inflamed RIs were created using 95 % RIs from horses classified as SH- (non-inflamed). Differences in median values of CBC parameters and inflammatory indices were determined using the Kruskal-Wallis test with Dunn's post-hoc analysis and a Bonferroni correction. Predictive value was determined using ROC analysis, and odds ratios were calculated to determine the value of industry and non-inflamed RIs in detecting inflammation. Significance was set at P ≤ 0.05. Results: All three inflammatory indices revealed greater median values in SH+ horses and predictive value greater than all other metrics (AUC=0.64, 0.64, 0.66, respectively). Horses falling above or below all three inflammatory index RIs (SII, SIRI, and AISI) were 6.32, 4.54, and 7 times more likely to be SH+. Additionally, a greater number of non-inflamed RIs yielded increased likelihood of SH+ categorization than industry RIs. Conclusions: These results suggest inflammatory indices and non-inflamed RIs may be a valuable tool to aid in the detection of inflammation in horses.
Copyright © 2025. Published by Elsevier Inc.
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Publication Date: 2025-10-01 PubMed ID: 41043566PubMed Central: PMC12614812DOI: 10.1016/j.jevs.2025.105705Google Scholar: Lookup
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  • Journal Article

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.

Overview

  • This study investigated changes in standard blood count parameters and derived inflammatory indices in horses to improve early detection of inflammation.
  • It aimed to develop reference intervals from horses without inflammation to better distinguish inflamed horses using routine blood tests.

Introduction and Objective

  • Inflammation is a common and critical condition affecting horse health, requiring timely detection for appropriate care.
  • Currently, acute phase proteins such as serum amyloid A (SAA) and haptoglobin are used as markers to detect inflammation but may not always be readily available.
  • The study’s objective was to explore whether complete blood count (CBC) parameters and derived inflammatory indices, which can be obtained from routine blood tests, vary reliably with inflammation.
  • The goal was to develop reference intervals (RIs) for these measurements based on horses confirmed to be non-inflamed, with the hypothesis that these “non-inflamed” RIs would improve diagnostic accuracy for inflammation detection.

Methods

  • The study was observational and included 199 horses categorized by inflammation status based on their serum amyloid A (SAA) and haptoglobin concentrations.
  • Two groups were defined:
    • SH+ (inflamed): 48 horses with elevated acute phase proteins.
    • SH- (non-inflamed): 150 horses with normal acute phase protein levels.
  • Complete blood count (CBC) parameters and various inflammatory indices were analyzed among these groups.
  • Reference intervals for the CBC parameters and indices were created from the SH- group using the 95% range to define normal limits.
  • Statistical analyses included:
    • Kruskal-Wallis test with Dunn’s post-hoc analysis and Bonferroni correction to evaluate differences in median blood parameters between groups.
    • Receiver Operating Characteristic (ROC) curve analysis to assess the predictive value of CBC parameters and inflammatory indices for inflammation detection.
    • Odds ratio calculation to determine how well these indices and newly derived non-inflamed RIs could identify inflamed (SH+) horses compared to standard industry RIs.
  • A significance level of P ≤ 0.05 was used for all analyses.

Key Concepts: Inflammatory Indices Used

  • SII: Systemic Immune-Inflammation Index
  • SIRI: Systemic Inflammatory Response Index
  • AISI: Aggregate Index of Systemic Inflammation
  • These indices combine counts of immune cells (such as neutrophils, lymphocytes, monocytes) as indicators of inflammatory status.

Results

  • All three inflammatory indices (SII, SIRI, and AISI) showed significantly higher median values in horses classified as inflamed (SH+), indicating these indices increase with inflammation.
  • Their predictive value based on ROC analysis was higher than individual CBC parameters, with Area Under the Curve (AUC) values around 0.64 to 0.66 for the indices, demonstrating moderate discriminative ability.
  • Odds ratios demonstrated strong associations:
    • Horses with inflammatory index values outside the non-inflamed reference intervals were:
      • 6.32 times more likely to be categorized as SH+ based on SII.
      • 4.54 times more likely for SIRI.
      • 7 times more likely for AISI.
  • Reference intervals derived from the non-inflamed group (SH-) were more effective in identifying inflammation than standard industry RIs, which could be based on mixed populations.
  • This indicates that creating RIs specifically from non-inflamed horses improves the sensitivity and specificity of these blood tests in detecting inflammation.

Conclusions and Implications

  • The study supports the use of inflammatory indices derived from routine CBC data to help detect inflammation in horses.
  • Reference intervals tailored to non-inflamed horses improve the diagnostic performance compared to general industry RIs.
  • This approach provides a potentially cost-effective and accessible tool for veterinary practitioners to identify inflammation early using common blood tests, without needing specialized acute phase protein assays.
  • Early inflammation detection can guide timely treatment and improve horse health outcomes.
  • Further research could focus on validating these indices and reference intervals in broader equine populations and in clinical settings.

Cite This Article

APA
Friend MM, McGaffigan EM, Hall SM, Staniar WB, Smarsh DN. (2025). Changes in equine complete blood count parameters and inflammatory indices with inflammation. J Equine Vet Sci, 155, 105705. https://doi.org/10.1016/j.jevs.2025.105705

Publication

Journal of equine veterinary science
ISSN: 0737-0806
NlmUniqueID: 8216840
Country: United States
Language: English
Volume: 155
Pages: 105705
PII: S0737-0806(25)00363-6

Researcher Affiliations

Friend, M M
  • Department of Animal Science, College of Agricultural Sciences, Pennsylvania State University, 439 Shortlidge Road, University Park, PA 16802, USA. Electronic address: mmf6157@psu.edu.
McGaffigan, E M
  • Department of Animal Science, College of Agricultural Sciences, Pennsylvania State University, 439 Shortlidge Road, University Park, PA 16802, USA.
Hall, S M
  • Department of Animal Science, College of Agricultural Sciences, Pennsylvania State University, 439 Shortlidge Road, University Park, PA 16802, USA.
Staniar, W B
  • Department of Animal Science, College of Agricultural Sciences, Pennsylvania State University, 439 Shortlidge Road, University Park, PA 16802, USA.
Smarsh, D N
  • Department of Animal Science, College of Agricultural Sciences, Pennsylvania State University, 439 Shortlidge Road, University Park, PA 16802, USA.

MeSH Terms

  • Animals
  • Horses
  • Inflammation / veterinary
  • Inflammation / blood
  • Horse Diseases / blood
  • Blood Cell Count / veterinary
  • Serum Amyloid A Protein / metabolism
  • Male
  • Female
  • Haptoglobins / metabolism
  • Reference Values

Grant Funding

  • T32 GM154124 / NIGMS NIH HHS

Conflict of Interest Statement

Declaration of competing interest None of the authors have any conflicts of interest to declare.

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