Analytical validation and establishment of reference intervals for a 'high-sensitivity' cardiac troponin-T assay in horses.
Authors: Shields E, Seiden-Long I, Massie S, Passante S, Leguillette R
Journal: BMC veterinary research
Summary
# High-Sensitivity Cardiac Troponin-T Assay: Now Validated for Equine Clinical Practice Whilst cardiac troponin-I assays have been established in horses for some years, human cardiology has moved toward 'high-sensitivity' troponin testing to improve detection of myocardial injury. Shields and colleagues rigorously validated the Roche high-sensitivity cardiac troponin-T (hscTnT) assay for equine use by evaluating analytical performance (precision, linearity, stability), establishing reference intervals in 125 non-competition horses and 178 racing Thoroughbreds, and demonstrating the assay's behaviour in two clinical cases of cardiac pathology. The assay performed reliably across its working range (3–391 ng/L), with acceptable within- and between-run precision and excellent correlation with existing troponin-I methods. Importantly, reference intervals differed between populations: non-competition horses showed upper 95th and 99th percentiles of 6.8 and 16.2 ng/L respectively, whilst racing Thoroughbreds were higher at 14.0 and 23.2 ng/L—a distinction that reflects the athletic demands on their cardiac tissue. For practitioners, this means hscTnT now offers improved sensitivity for detecting subtle myocardial damage in acute illness, arrhythmia, or suspected heart disease, though users must apply the appropriate reference interval for their horse's type and recognise that diurnal and between-day variations are negligible, simplifying interpretation.
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Practical Takeaways
- •hscTnT is now a reliable cardiac biomarker for horses and can be used clinically; reference intervals differ between racing and non-racing populations so use appropriate comparison values
- •Significantly elevated troponin-T levels (>20 ng/L in non-racing or >25 ng/L in racing horses) suggest cardiac pathology and warrant further cardiac investigation
- •This assay matches human cardiology standards and enables better detection of subtle cardiac damage in performance and sport horses
Key Findings
- •High-sensitivity cardiac troponin-T (hscTnT) assay demonstrates acceptable analytical validation with within-run CV 5.4-14.9% and between-run CV 8.4-9.0%
- •Reference intervals established: 6.8-16.2 ng/L (95th-99th percentile) for non-competition horses and 14.0-23.2 ng/L for racing Thoroughbreds
- •hscTnT assay shows excellent correlation with cTnI assay (R²=0.9996) across wide concentration range of 8.0-3535.0 ng/L
- •Cardiac pathology cases demonstrated markedly elevated hscTnT levels (220.9 and 5723.0 ng/L) confirming clinical utility of the assay