Which test is commonly used for diagnosing heartworm disease in dogs?

The antigen test is the standard diagnostic tool for detecting heartworm disease in dogs. This test works by identifying specific proteins, known as antigens, that are produced by female adult heartworms. Since heartworms reside in the dog's heart and surrounding blood vessels, the presence of these antigens in the bloodstream indicates an active infection.

The antigen test is highly sensitive and can provide accurate results even in cases with a low number of heartworms. It is particularly effective because it can differentiate between active infections and the presence of dead or immature worms, which may not elicit a significant immune response.

In contrast, the other options do not directly diagnose heartworm disease. A complete blood count (CBC) may reveal some anemia or other indirect signs related to parasitic infections, but it is not specific for heartworms. A urinalysis can provide insight into kidney function and other systemic issues but does not test for heartworm infection directly. Similarly, a skin scraping is typically used to diagnose skin conditions and parasites like mites and is not relevant for detecting internal parasites like heartworms.

Thus, the antigen test stands out as the most reliable method for accurately diagnosing heartworm disease in dogs.