High-Sensitivity Cardiac Troponin I

This assay is offered by the Texas A&M VMTH Cardiology Service.

Reference Intervals

• Canine: <20 to 168 pg/mL
• Feline: <8 to 190 pg/mL

Sample Requirements & Shipping Information

• 0.6 mL of non-hemolyzed serum. Withholding food for 8 to 12 hours is recommended.
• Samples should be frozen prior to shipment and shipped with dry ice or sufficient ice packs to remain frozen during shipment.

Turnaround

• 3-5 business days after receipt of samples.

Interpretation

Dogs

cTnI Concentration	Interpretation
< 20 to 49 pg/mL	Result is within the reference interval. Active myocardial injury is unlikely.
50 to 168 pg/mL	Result is within the upper part of the reference interval. This can be normal in aging dogs, but active myocardial injury is also possible. If clinical signs of heart disease are present, additional diagnostic workup is recommended. Please see additional comments below.
≥ 169 pg/mL	Increased troponin I concentration. Active myocardial injury is likely, additional diagnostic workup is recommended.

TNIH concentrations in healthy dogs and dogs with suspected myocardial injury overlap slightly and so either false positive or false negative results may occur with this test. Consequently, results of the high-sensitivity cardiac troponin I assay must be interpreted in conjunction with other clinical data. Most healthy dogs (confirmed with echocardiogram and ECG) have high-sensitivity cardiac troponin I concentrations < 135 pg/mL, but in one study, 1 of 39 healthy dogs had a higher concentration. Nearly all dogs with suspected myocardial injury have concentrations > 50 pg/mL but about 50% have concentrations < 135 pg/mL. Finally, in healthy dogs, TNIH concentrations are positively correlated with age.

Cats

cTnI Concentration	Interpretation
<8 to 190 pg/mL	Result is within the reference interval. Active myocardial injury is unlikely.
≥191 pg/mL	Result is within the upper part of the reference interval. This can be normal in aging dogs, but active myocardial injury is also possible. If clinical signs of heart disease are present, additional diagnostic workup is recommended. Please see additional comments below.

Cats with suspected myocardial injury were found to have higher cardiac troponin I concentrations than healthy cats. However, the diagnostic accuracy of this test has not been fully characterized in this species. Because of this, results of the TNIH assay must be interpreted in conjunction with other clinical data. A correlation between cardiac troponin I and age was not found in healthy cats.

Other Species

This assay can measure cardiac troponin in variety of other animal species. However, reports will not include reference intervals or interpretations.

Further Reading

1. Wesselowski S, Lidbury J, Saunders AB, Gordon SG, Suchodolski JS, Steiner JM. Analytical validation, sample stability, and clinical evaluation of a new high-sensitivity cardiac troponin I immunoassay for use in dogs, with comparison to a previous ultrasensitive assay. PLoS One 2023;18:e0288801.
2. Lidbury JA, Meyers RC, Saunders AB, Vitt JP, Gordon SG, Lim S, Fries RC, Suchodolski JS, Steiner JM, Wesselowski S. Analytical validation and clinical evaluation of a high-sensitivity cardiac troponin I immunoassay for use in cats. PLoS One 2026;21:e0346522.