Skip to content

Cryptosporidium Stool Antigen Test

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

This test detects the presence of Cryptosporidium parasites in your stool. Cryptosporidium is a microscopic parasite that can cause gastrointestinal illness, often in people with weakened immune systems.

Quick summary

["Checks for a parasite linked to stomach cramps, diarrhea, and dehydration."]

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

Key facts at a glance

LOINC
110645-9
Short code
Cryptosp Ag Msmt Stl
Synonyms
Cryptosp Ag Msmt Stl
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

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you’ve experienced persistent diarrhea, especially after traveling to areas with poor sanitation, or if you have a weakened immune system (e.g., from HIV, chemotherapy, or other conditions). It’s also used to confirm infection in people with symptoms like nausea, abdominal pain, or unexplained weight loss.

How the Test Works

The test looks for Cryptosporidium parasite DNA or antigens in your stool sample. A healthcare professional will collect a sample, which is then analyzed in a lab to detect the parasite’s presence.

Sample Collection

You’ll need to provide a fresh stool sample (usually collected in a special container) during your visit. If testing is done at home, follow the instructions provided to ensure accuracy. Do not use toilet water or cleaning solutions in the sample.

What to Expect After the Test

Results are typically ready within 24–48 hours. If the test is positive, your provider will discuss next steps, which may include treatment, monitoring, or further testing to rule out other causes of your symptoms.

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

Stool Cryptosporidium Test

Frequently asked questions

What does a positive result mean?
A positive result confirms the presence of Cryptosporidium parasites in your stool, indicating active infection. This means you may have symptoms like diarrhea, stomach cramps, or nausea. Your provider will work with you to manage symptoms, determine if treatment is needed, and monitor your recovery.
Can I still spread the parasite after testing positive?
Yes, Cryptosporidium is highly contagious. You can spread the parasite through contaminated food, water, or direct contact with an infected person’s stool. Practice good hand hygiene, avoid sharing food utensils, and wash hands thoroughly after using the toilet. Avoid preparing food for others if you’re symptomatic.
How long does it take to recover from Cryptosporidium infection?
Recovery time varies, but symptoms can last weeks to months, especially in people with weakened immune systems. Most healthy adults recover within 2–6 weeks. Supportive care (like staying hydrated) and avoiding stress on your digestive system can help speed up recovery. Follow your provider’s advice for follow-up testing if needed.
  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