Evaluation of the trūRapid™ FOUR heartworm antigen test: a reliable point-of-care diagnostic tool for heartworm detection in dogs

Abstract Background Heartworm disease, caused by Dirofilaria immitis, is a globally distributed and clinically significant cardiopulmonary condition affecting dogs and other animal species. Dogs typically lack overt clinical signs in the early stages of infection, and disease progression can lead to worsening clinical signs and poor prognosis. The purpose of this study was to evaluate the performance of the tr?Rapid™ FOUR heartworm antigen test (Antech Diagnostics) for the detection of D. immitis antigen in canine serum samples and to compare its performance with another commercially available point of care (POC) heartworm antigen test, specifically the SNAP® 4DX® Plus (IDEXX), using DiroCHEK® (Zoetis) as the reference test. Methods A total of 350 canine remnant serum samples were evaluated using tr?Rapid™ FOUR, SNAP® 4DX® Plus, and DiroCHEK® as per manufacturers' instructions. Results For samples positive at DiroCHEK® (n = 149), the sensitivity of the tr?Rapid™ FOUR heartworm antigen test was 98.7% (95% CI 94.3-99.6%), with a specificity of 100% (95% CI 98.2-100%) for samples negative at DiroCHEK® (n = 201). The tr?Rapid™ FOUR showed excellent agreement with another available POC test, the SNAP® 4DX® Plus (0.994 ? agreement, 95% CI 0.983-1.000). Conclusions The findings demonstrate that the tr?Rapid™ FOUR heartworm antigen test provides reliable diagnostic accuracy, ease of use, and a fast time to result (10 min), making it a robust POC option for detecting canine heartworm infection. Its performance is comparable to the reference laboratory ELISA test, DiroCHEK®, and another commercially available POC test, SNAP® 4DX® Plus. Overall, the results support the use of the tr?Rapid™ FOUR heartworm antigen test as a dependable clinical tool for the detection and management of heartworm infection in dogs.