Toxicity Screening for Giardia duodenalis (Giardia intestinalis) Antigen

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you’ve recently traveled to regions with higher risk of Giardia infection, experienced persistent diarrhea, abdominal pain, or bloating, or if you’ve been exposed to contaminated water. It’s also sometimes used in outbreaks or after testing for other gastrointestinal infections.

What to Expect During Testing

Blood is drawn from a vein in your arm. The sample is tested for Giardia antigens using a sensitive immunoassay method. Results are typically available within 24–48 hours.

What the Results Mean

A positive result indicates recent exposure to Giardia and may require further testing (like stool samples) or treatment with antiparasitic medications. A negative result means no detectable antigens were found in this sample, but Giardia could still be present in stool.

Common Causes of False Results

False negatives are more likely if the test was taken too early after exposure or if stool samples (not blood) would be more appropriate for diagnosis. False positives are rare but can occur if other substances interfere with the test.