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Cryptosporidium Antigen in Stool (Qualitative)

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

This test checks for the presence of Cryptosporidium parasites in your stool, which can cause diarrhea and other gastrointestinal symptoms.

Quick summary

["A positive result may indicate an infection that requires medical attention."]

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

Key facts at a glance

LOINC
20781-1
Short code
Cryptosp Stl Ql Acid fast Stn
Synonyms
Cryptosp Stl Ql Acid fast Stn
Category
coagulation
Sample
stool
Container
Clean container
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
acid-fast-stain
CPT
84484
SNOMED
302774002
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 (such as from HIV/AIDS or chemotherapy). It’s also used to diagnose infections in children or those with chronic health conditions like cystic fibrosis.

What to Expect Before the Test

No special preparation is needed, but you may be asked to collect a fresh stool sample in a provided container. If you’re on antibiotics, inform your provider, as they might affect test results.

What the Results Mean

A positive result means Cryptosporidium parasites were found in your stool, confirming an infection. A negative result means no parasites were detected in this sample, but you may still need further testing or monitoring if symptoms persist.

Possible Side Effects or Considerations

There are no known side effects from this test, but false negatives can occur if the sample isn’t collected properly or if the infection is in an early stage. Follow-up testing may be needed if symptoms continue.

Reference range

Adult: 10-40 U/LN/A

Specimen: stool

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Stool Cryptosporidium Test

Frequently asked questions

How does this test help doctors?
This test helps identify Cryptosporidium infections, which can cause severe diarrhea, especially in immunocompromised individuals. Early detection allows for prompt treatment and management of symptoms, reducing the risk of dehydration or complications.
What if I have symptoms but the test is negative?
If you continue to have diarrhea or other symptoms after a negative result, your doctor may order additional tests (like stool cultures) or check for other possible causes of your illness.
Can I get this test at home?
Some healthcare providers offer at-home stool collection kits for this test. Always follow the instructions provided to ensure accurate results and proper handling of 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