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Giardia lamblia Antigen in Stool (Qualitative)

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

This test checks for the presence of Giardia lamblia, a microscopic parasite that can cause intestinal infections.

Quick summary

["A positive result may indicate an infection needing treatment."]

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

Key facts at a glance

LOINC
48060-8
Short code
G lamblia+Cryptosp Ag Stl Ql
Synonyms
G lamblia+Cryptosp Ag Stl Ql
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
CPT
85610
SNOMED
396252006
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

What Is Giardia Lamblia?

Giardia lamblia is a single-celled parasite that can live in the intestines. It’s often spread through contaminated water or food and can cause symptoms like stomach cramps, diarrhea, bloating, and nausea. In some cases, it may not cause symptoms at all.

How Is This Test Performed?

You’ll provide a stool sample, which is tested to detect Giardia lamblia antigens—specific molecules from the parasite that indicate an active infection. The test is qualitative, meaning it only tells you if the parasite is present, not how severe the infection is.

Why Might You Need This Test?

Your healthcare provider may recommend this test if you have symptoms like persistent diarrhea, stomach pain, or bloating, especially after traveling to areas with poor sanitation or if you’ve been exposed to contaminated water.

What Are Possible Results?

A positive result means Giardia lamblia antigens were found in your stool, suggesting an active infection. A negative result means the test did not detect the parasite at the time of testing. Repeat testing may be needed if symptoms persist.

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.

◆Associated findings1

Short name

Giardia stool test

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on the lab’s processing schedule. Your provider will discuss the results with you during your follow-up visit.
Can I take antibiotics before the test?
Yes, but inform your healthcare provider beforehand. Antibiotics can affect the test results, so they may adjust your treatment plan accordingly.
What if my symptoms improve before getting the results?
Even if symptoms improve, the test is still important to confirm or rule out an infection. Follow-up testing may be needed if symptoms return or if your provider suspects ongoing exposure.
  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