Giardia Antigen in Stool (Qualitative, Rapid Immunoassay)
This test detects the presence of Giardia intestinalis parasites in your stool, helping identify if you have an infection caused by these microscopic organisms.
["A positive result may indicate giardiasis, a common intestinal infection often spread through contaminated food or water."]
Key facts at a glance
- LOINC
- 91761-7
- Short code
- Giardia Ag Stl Ql IA.rapid
- Synonyms
- Giardia Ag Stl Ql IA.rapid
- Category
- chemistry
- Sample
- stool
- Container
- Clean container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia-rapid
- Specimen volume
- 5 g
- Stability
- Refrigerated: 24h, Frozen: 7d
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may recommend this test if you have symptoms like stomach cramps, diarrhea, bloating, or gas. It’s also used to diagnose giardiasis in people with no obvious symptoms or after treatment to confirm the infection is cleared.
How the Test Works
A small sample of your stool is tested using a rapid immunoassay method. This detects specific proteins (antigens) produced by Giardia parasites, allowing for quick identification of infection without needing to culture the organism.
Sample Collection
You’ll need to collect a fresh stool sample (preferably within 24 hours) using a provided collection kit. Follow the instructions carefully to ensure the sample is representative and tested promptly for accurate results.
What to Expect After Testing
Results are typically available within 15–60 minutes. A positive result means Giardia antigens were found, suggesting an active infection. A negative result means no detectable antigens were found at the time of testing, but reinfection is possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Giardia is a common cause of watery diarrhea, abdominal pain, and malabsorption in both children and adults. Early diagnosis is important to prevent dehydration, especially in vulnerable populations like infants, elderly individuals, or those with weakened immune systems. Treatment with appropriate antibiotics can resolve symptoms and clear the infection.
Short name
Giardia stool test (rapid)
Frequently asked questions
What does a positive result mean?
Can I still spread Giardia even if my symptoms have improved?
How long does it take to get results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy