Lactose Intolerance Screening (Qualitative Fecal Hydrogen Gas)
This test checks for lactose intolerance by measuring small amounts of hydrogen gas produced in your gut when lactose isn’t properly digested.
["A simple breath test to help determine if lactose digestion issues may be affecting your digestion or symptoms."]
Key facts at a glance
- LOINC
- 96813-1
- Short code
- Goat milk cheese IgE Qn
- Synonyms
- Goat milk cheese IgE Qn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
How the Test Works
You’ll drink a lactose-containing liquid while wearing a special mask to collect your breath samples. Your body naturally produces hydrogen gas if it can’t break down lactose, which your test detects.
What to Expect Before the Test
No special preparation is needed, but avoid dairy products for 3–4 days before testing to ensure accurate results. Wear comfortable clothing and bring your mask if you need to.
Possible Results and Their Meaning
A positive result (detecting hydrogen gas) suggests lactose intolerance, while a negative result indicates normal digestion of lactose. Follow-up may include dietary adjustments or further testing.
Common Symptoms Linked to This Test
If lactose intolerance is suspected, this test may help identify digestive symptoms like bloating, gas, or diarrhea after consuming dairy products.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Fecal Hydrogen Gas (Qualitative)
Frequently asked questions
Why did my doctor order this test?
What if my test results are positive?
How long does it take to get results?
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