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Gastrointestinal (GI) Tract Fecal Immunochemical Test for Occult Blood (FIT) with Qualitative Detection

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

This test checks for hidden (occult) blood in your stool, which may indicate bleeding in your digestive system.

Quick summary

["A simple stool test to detect potential GI bleeding early."]

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

Key facts at a glance

LOINC
42909-2
Short code
Hgb sp1 Gast gastro Ql
Synonyms
Hgb sp1 Gast gastro Ql
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
7 N/A – 20 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84484
SNOMED
302774002
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 detects the presence of hemoglobin or related proteins in your stool, which appear when small amounts of blood are present but not visibly apparent. This is done using a chemical reaction that changes color if blood is present.

Why It’s Done

Doctors may recommend this test if you have symptoms like unexplained weight loss, changes in bowel habits, or if you’re at higher risk for conditions like colorectal cancer.

Sample Collection

You’ll collect a small sample of your stool using provided collection kits. The sample is then sent to a lab for testing. No special preparation is needed, but you should avoid using certain medications or foods that might interfere with results.

What to Expect

The test is quick and painless. You’ll likely receive results within a few days, depending on lab processing times.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

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

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is primarily used as a screening tool to identify potential GI bleeding. Positive results may prompt further diagnostic testing, such as colonoscopy, to determine the cause. It’s not a definitive test for cancer but is an important first step in early detection.

Short name

FIT (qualitative)

Frequently asked questions

What causes false positives or negatives in this test?
False positives can occur due to certain foods (like red meat, tomatoes, or supplements), medications, or conditions like hemorrhoids or anal fissures. False negatives may happen if the sample isn’t collected properly or if bleeding is very small. Always follow your healthcare provider’s instructions for accurate results.
How often should I get this test?
The frequency depends on your health history and risk factors. Typically, screening begins at age 50 for average-risk individuals, but your doctor may recommend earlier or more frequent testing based on your personal or family medical history.
Can I eat or drink anything before the test?
No special diet is required, but avoid using certain medications (like NSAIDs) or supplements that might interfere with the test. Follow your healthcare provider’s instructions for the best 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