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Giardia lamblia Antigen in Stool (Qualitative/Quantitative Immunoassay)

Published: August 9, 2026Updated: August 16, 2026

This test detects the presence of Giardia lamblia parasites in your stool, helping identify infections caused by this common intestinal parasite.

Quick summary

["A Giardia stool test can help diagnose symptoms like diarrhea, stomach cramps, or bloating caused by Giardia infection."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
91676-7
Short code
G lamblia Ag Stl Ql IA.rapid
Synonyms
G lamblia 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 Matters

Giardia is a single-celled parasite that can cause gastrointestinal issues, including chronic diarrhea, nausea, and abdominal pain. Detecting it early is important for proper treatment and preventing spread.

What to Expect Before the Test

No special preparation is needed, but you may be asked to collect a fresh stool sample in a provided container. Avoid using toilet paper or cleaning products in the sample.

Your sample will be tested using an immunoassay method to detect Giardia antigens. Results are typically available within 24–48 hours.

The test looks for specific proteins (antigens) left behind by the parasite in your stool, rather than the live parasite itself.

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.

A positive result does not always mean you have an active infection—sometimes the parasite may be present but not causing symptoms. Follow-up testing may be needed if symptoms persist.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is critical for diagnosing Giardia infections, which can cause severe or chronic gastrointestinal symptoms. It helps doctors determine if treatment with antiparasitic medications is needed, especially in cases of travel-related exposure, contaminated water, or close contact with infected individuals.

Short name

Giardia stool test

Frequently asked questions

How long does it take to get my results?
Results are usually available within 24 to 48 hours, but timing may vary by lab. You’ll be notified once they’re ready.
Can I take antibiotics before this test?
Yes, if you’re prescribed antibiotics for a suspected Giardia infection, you can take them before testing. However, inform your doctor or lab technician about any medications you’re taking to avoid interference with results.
Is this test covered by insurance?
Check with your insurance provider to confirm coverage, as testing for parasites may be covered if symptoms or risk factors (like travel history) warrant it. Your doctor can also help clarify coverage details.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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