Cryptosporidium Stool Antigen Test (Qualitative)

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like persistent diarrhea, abdominal pain, or weight loss—especially if you’ve traveled to areas with poor sanitation, have a weakened immune system, or are in contact with someone who has been infected. It’s also used to diagnose or monitor cryptosporidiosis in people with HIV/AIDS or other immune conditions.

What to Expect Before the Test

No special preparation is needed. You may be asked to collect a fresh stool sample in a provided container. If you’re taking antibiotics or have recently had a bowel movement, let your provider know to ensure accurate results.

What Happens During the Test

A healthcare professional will examine your stool sample under a microscope or use a rapid immunoassay (test kit) to detect Cryptosporidium antigens. Results are usually available within hours or a few days, depending on the method used.

What the Results Mean

A positive result means Cryptosporidium parasites are present in your stool, confirming an active infection. A negative result means no parasites were found in the sample, but symptoms could still be caused by other factors. Follow-up testing or additional evaluation may be needed if symptoms persist.