Cryptosporidium Stool Antigen Test (Qualitative)
This test detects the presence of Cryptosporidium parasites in your stool, which can cause diarrhea and other gastrointestinal symptoms. It helps identify infections that may require treatment or further evaluation.
["Check for a parasite infection that can cause long-lasting diarrhea, especially in immunocompromised individuals."]
Key facts at a glance
- LOINC
- 566-0
- Short code
- Cryptosp Ag Spec Ql IF
- Synonyms
- Cryptosp Ag Spec Ql IF
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- if
- CPT
- 85610
- SNOMED
- 396252006
- 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 Is Done
Your healthcare provider may recommend this test if you have symptoms like persistent diarrhea, abdominal pain, or weight loss, particularly if you’ve traveled to areas with poor sanitation or have a weakened immune system. It’s also used to monitor infections in people with HIV/AIDS or other conditions that suppress immunity.
How the Test Works
The test uses a stool sample to detect Cryptosporidium parasites through an immunoassay method. If parasites are present, the test will identify them, helping confirm an infection.
Sample Collection
You’ll need to provide a fresh stool sample, ideally collected in a special container provided by your lab. Avoid using toilet paper or urine in the sample. Follow your provider’s instructions for proper collection and handling.
What to Expect After Testing
Results are typically available within 24–48 hours. If the test is positive, your provider may recommend further testing or treatment to address the infection. A negative result doesn’t always mean you’re clear of the parasite, so retesting may be needed if symptoms persist.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
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
Crypto Stool Test (Qual)
Frequently asked questions
Cryptosporidium is a common cause of watery diarrhea, often lasting weeks or months. It’s particularly dangerous for people with weakened immune systems, such as those with HIV/AIDS, transplant recipients, or individuals on certain medications that suppress immunity. Early detection helps prevent dehydration and guides treatment decisions.
If you’ve had recent contact with someone who has a Cryptosporidium infection, you may still test positive even if you’re not showing symptoms. This test won’t show if you were exposed but haven’t yet developed symptoms.
No special preparation is needed, but avoid eating or drinking for 1–2 hours before collecting the sample to ensure accuracy.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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