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Giardia lamblia Antigen in Stool (Qualitative)

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

This test detects the presence of Giardia lamblia, a microscopic parasite that can cause intestinal infections, often leading to symptoms like diarrhea, stomach cramps, or bloating.

Quick summary

["Checks for a parasite that may cause digestive issues."]

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

Key facts at a glance

LOINC
91675-9
Short code
G lamblia+C parvum Ag Pnl Stl IA.rapid
Synonyms
G lamblia+C parvum Ag Pnl Stl IA.rapid
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia-rapid
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you’ve experienced persistent diarrhea, abdominal pain, or other gastrointestinal symptoms that could be linked to a parasite infection, especially if you’ve traveled to areas with poor sanitation or had recent exposure to contaminated water.

What to Expect Before the Test

No special preparation is needed. Bring a fresh stool sample to your appointment. If you’re using laxatives or medications that affect bowel movements, let your doctor know beforehand.

What the Test Results Mean

A positive result indicates the presence of Giardia lamblia antigens in your stool, suggesting an active infection. A negative result means the parasite was not detected in this sample, but infection could still be present. Follow-up testing or additional samples may be needed for confirmation.

Common Symptoms of Giardia Infection

Symptoms may include watery diarrhea, stomach cramps, bloating, gas, nausea, and sometimes a foul-smelling stool. Some people may not have symptoms at all, especially children or those with weakened immune systems.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Giardia stool antigen test

Frequently asked questions

Giardia is a common cause of traveler’s diarrhea and can lead to chronic digestive issues if untreated. It spreads through contaminated food or water and can affect anyone, but children and immunocompromised individuals are at higher risk of severe symptoms.
This test helps confirm a diagnosis quickly, allowing for prompt treatment with antiparasitic medications to relieve symptoms and prevent spread.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule. Your doctor will discuss the results with you during your follow-up visit.
Can I eat or drink normally before the test?
Yes, you can eat and drink as usual. Avoid using stool softeners or laxatives unless instructed by your doctor, as they may affect the sample.
  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