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Giardia lamblia stool antigen test (qualitative, rapid immunoassay)

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

This test detects the presence of Giardia lamblia parasites in your stool, which can cause intestinal infections.

Quick summary

["A positive result may indicate an infection with Giardia, a common cause of diarrhea."]

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

Key facts at a glance

LOINC
49232-2
Short code
G lamblia+Cryptosp Ag Stl Ql Rapid
Synonyms
G lamblia+Cryptosp Ag Stl Ql Rapid
Category
coagulation
Sample
stool
Container
Clean container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rapid-less-than-minutes
CPT
85610
SNOMED
396252006
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 persistent diarrhea, stomach cramps, bloating, or nausea, especially after traveling to areas with poor sanitation or if you’ve been exposed to contaminated water.

What to Expect Before the Test

No special preparation is needed. You’ll provide a fresh stool sample in a provided container. The test is quick and done in the lab or at a clinic.

What the Results Mean

A positive result means the test detected Giardia parasite antigens in your stool, suggesting an active infection. A negative result means no detectable antigens were found, but infection could still be present if symptoms persist.

Common Symptoms of Giardia Infection

Symptoms may include watery diarrhea, stomach pain, gas, nausea, or fatigue. Some people may have no symptoms at all, especially children or those with weakened immune systems.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: stool

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Giardia is a common parasitic infection that can lead to chronic diarrhea, malnutrition, and dehydration if untreated. Early detection with this test helps guide treatment and prevents spread to others.

Short name

Giardia stool test (qualitative)

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your provider will discuss the results with you during your follow-up visit.
Can I eat or drink before giving the stool sample?
Yes, you can eat and drink normally before providing the sample. Avoid using toilet cleaners or toilet paper that may contain chemicals that could interfere with the test.
What if my test is negative but I still have symptoms?
A negative result means no Giardia antigens were detected in this sample. However, symptoms could persist due to other causes or lingering infection. Follow-up testing or a different sample may be recommended if symptoms continue.
  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