Cryptosporidium stool antigen test (qualitative)

What This Test Measures

The test looks for Cryptosporidium antigens in your stool sample. Antigens are small pieces of the parasite’s structure that the immune system can recognize. This qualitative test determines whether these antigens are present, not how much.

Why It’s Done

Doctors may order this test if you have persistent diarrhea (lasting more than a few days), especially if it’s severe, bloody, or accompanied by other symptoms like weight loss or abdominal pain. It’s also used in people with weakened immune systems (e.g., from HIV/AIDS, chemotherapy, or organ transplants) who may be more susceptible to infections like Cryptosporidium.

Sample Collection

You’ll need to provide a fresh stool sample (usually collected in a special container) for testing. If you’re unsure how to collect it, follow your healthcare provider’s instructions. The sample should be delivered to the lab as soon as possible for accurate results.

What to Expect After Testing

Results are typically available within 24 to 48 hours. If the test is positive, further testing (like microscopy) may be needed to confirm the diagnosis and guide treatment. A negative result doesn’t always rule out infection, especially if symptoms are mild or the infection is in an early stage.