Evaluation of a rapid test for point-of-care detection of cardiac troponin I in serum of healthy and diseased dogs and cats

Objectives
(1) To compare the results of a rapid test for qualitative detection of cardiac troponin I (cTnI) values >1 ng/mL with those obtained using a reference quantitative method and (2) to perform a semiquantitative assessment of rapid test results using this point-of-care (POC) assay.

Design
Prospective cross-sectional study from April 2015 to November 2020.

Setting
Secondary referral hospital.

Animals
Eighty dogs and 20 cats, with and without cardiovascular disease.

Interventions
None.

Measurements and Main Results
Serum samples were obtained, and cTnI rapid test was conducted in parallel with chemiluminescence assay (reference standard). Positive results from the rapid test were further classified as mild and strong positives, based on subjective assessment of the color intensity of the test line. Rapid test was deemed valid in all patients. There was agreement for positive samples between the qualitative and quantitative techniques in 31 dogs and 5 cats, and for negative samples in 43 dogs and 13 cats, resulting in a strong and moderate agreement, respectively. There was a significant difference between color scale groups.

Conclusions
The rapid test assessed provides a feasible POC option to determine concentrations of cTnI >1 ng/mL in dogs and cats and shows a moderate to strong agreement with a validated conventional quantitative assay. Furthermore, semiquantitative assessment allows estimation of the magnitude of the elevation.