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Fecal Immunochemical Test for Occult Blood (FIT) - Probe-Based

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

This test detects hidden (occult) blood in your stool using a special probe to help identify possible gastrointestinal bleeding.

Quick summary

["A simple stool test to check for hidden blood that may signal bleeding in your digestive system."]

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

Key facts at a glance

LOINC
61362-0
Short code
E faecalis DNA Spec Ql NAA+probe
Synonyms
E faecalis DNA Spec Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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

What This Test Measures

The test uses a chemical probe to detect the presence of hemoglobin (the protein in blood that carries oxygen) in your stool. Even small amounts of hidden blood can be detected, which may indicate conditions like colorectal cancer, ulcers, or other gastrointestinal issues.

Why It’s Done

Your healthcare provider may recommend this test if you have symptoms like unexplained weight loss, changes in bowel habits, or if you’re at higher risk for gastrointestinal bleeding. It’s also sometimes used as a screening tool for colorectal cancer.

How It’s Performed

You’ll collect a small sample of stool in a provided container and return it to your lab. The probe detects hidden blood in the sample, and results are typically reported as positive or negative for occult blood.

What the Results Mean

A positive result means hidden blood was found, which may require further testing (like a colonoscopy) to find the cause. A negative result means no hidden blood was detected, but it doesn’t rule out other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

FIT Probe Test

Frequently asked questions

What does a positive result mean?
A positive result suggests hidden blood was found in your stool, which could indicate bleeding from the digestive tract. Your doctor will likely order additional tests, such as a colonoscopy, to investigate further.
How often should I get this test?
The frequency depends on your risk factors and healthcare provider’s recommendations. Some people get it as part of routine screening, while others may need it more often if they have risk factors like a family history of colorectal cancer or symptoms like unexplained weight loss or blood in stool.
Can I eat or drink anything before the test?
You can eat and drink normally before the test, but avoid using over-the-counter stool softeners or laxatives that could interfere with the results.
  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