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Anti-Giardia lamblia IgA Antibody (Serum)

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

This test measures the presence of IgA antibodies in your blood to help detect an infection caused by *Giardia lamblia*, a common intestinal parasite.

Quick summary

["IgA antibodies may indicate past or current infection by Giardia, which can cause digestive symptoms like diarrhea, bloating, or stomach pain."]

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

Key facts at a glance

LOINC
16898-9
Short code
G lamblia65 Ag Stl Ql
Synonyms
G lamblia65 Ag Stl Ql
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

What This Test Measures

IgA antibodies are a type of immune protein your body produces in response to *Giardia lamblia* infection. If detected, they suggest your immune system has recognized and reacted to the parasite. This test helps doctors diagnose giardiasis, especially in cases where stool tests may be inconclusive or when symptoms persist despite negative stool exams.

Why It Might Be Ordered

Your healthcare provider may recommend this test if you have persistent digestive symptoms (e.g., chronic diarrhea, bloating, or nausea) that don’t improve with standard treatments, or if you’ve been exposed to *Giardia* and other tests (like stool cultures) have been negative.

What to Expect Before the Test

No special preparation is needed. A blood sample will be drawn from a vein, typically in your arm. You may feel slight discomfort, but it usually lasts only a few minutes.

What the Results Mean

Positive results indicate your body has produced IgA antibodies to *Giardia lamblia*, suggesting past or ongoing infection. Negative results mean no detectable antibodies were found, but this doesn’t rule out infection if symptoms persist—additional testing may be needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Giardia infections are common in travelers, those with weakened immune systems, or in settings with poor sanitation. While often self-limiting, untreated infections can cause long-term digestive issues or malnutrition. Early diagnosis helps guide treatment with antiparasitic medications.

Short name

IgA Antibody to Giardia

Frequently asked questions

Will this test show if I have *Giardia* right now?
This test detects antibodies produced by your immune system in response to *Giardia lamblia*, not the parasite itself. It may indicate past infection or ongoing exposure, but it doesn’t confirm active infection without additional testing (e.g., stool samples).
Can I take antibiotics before this test?
Antibiotics may suppress the immune response, potentially affecting antibody detection. If you’ve recently taken antibiotics, let your doctor know so they can interpret results carefully.
Does this test replace stool tests for *Giardia*?
No, this test is complementary. Stool tests (e.g., culture or antigen detection) are often preferred for diagnosing active infection. Your doctor may use results from both tests to guide treatment.
  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