Feline parvovirus (FPV) is one of the most common causes of acute hemorrhagic enteritis, with high mortalities in kittens. As clinical diagnosis is often indecisive, the aim of our study was to evaluate the diagnostic accuracy of in-clinic rapid tests for the detection of FPV infection in cats. To this end, we contrasted the most reliable diagnostic technique—PCR—with the rapid diagnostic kit for FPV antigen. A total of 100 stool samples were collected from cats suspected of being infected with FPV. A vaccination history was reported for all sampled cats. Every sample underwent both PCR and the rapid diagnostic test, with the results being compared. Anorexia, bloody diarrhea, severe dehydration, hypothermia, and vomiting were the most common clinical findings significantly associated with parvovirus-infected cats. 35 out of 100 clinically ill cats were FPV positive (35%) using the rapid screening test, while 43 (43%) of the tested samples were PCR positive. Overall, the two tests found FPV infection in 32 cases and ruled it out in 54. The PCR technique confirmed the infection in 11 cases that their rapid testing were negative. Rapid antigen-based screening assays demonstrated sensitivity and specificity of 74.42% and 94.74%, respectively. In conclusion, a positive result certainly indicates FPV infection, while a negative result does not rule out parvoenteritis from the differential diagnosis, especially in cats exhibiting clinical symptoms. It is possible to anticipate increased sensitivity if the test is run right following sample collection.