Test library
Vitamin B3 Niacin Test
This blood test measures vitamin B3 (niacin) to help evaluate deficiency. Niacin supports energy metabolism and normal function of the skin, digestive tract, and nervous system, so low levels can affect several systems.
Order Vitamin B3 Niacin Testing
Order online and visit a local collection site, or choose an at-home kit where available. No referral and no insurance required.
Order Vitamin B3 Niacin Testing- Typical turnaround
- 1-3 business days
- Starting price
- From $49
- Results
- Confidential, online
Quick answer
The vitamin B3 test measures niacin, a water-soluble vitamin the body uses to convert food into energy. Niacin also supports the skin, the digestive tract, and the nervous system. The test is ordered when a deficiency is suspected because of poor nutrition, certain medical conditions, or long-term use of some medications. A blood sample is used, and results are interpreted with diet and symptoms.
What this test measures
Vitamin B3, also called niacin, is a building block for the coenzymes NAD and NADP, which take part in hundreds of reactions that release energy from food. Like other B vitamins, niacin helps cells process carbohydrates, fats, and proteins. It also plays a role in repairing DNA and in signaling within cells.
Testing may measure niacin or its metabolites in blood or urine. Some laboratories assess the ratio of niacin metabolites to creatinine to gauge status. The collection is a standard blood or urine sample, and the report compares the finding with a method-specific reference range.
Deficiency is uncommon in people with varied diets, since niacin is found in meat, fish, poultry, nuts, and fortified grains, and the body can make some from the amino acid tryptophan. When it does occur, it can affect the skin, digestion, and mental function. Testing helps a healthcare provider decide whether niacin status is relevant to symptoms.
- Niacin (vitamin B3)
- Nicotinamide
- Nicotinamide adenine dinucleotide (NAD) metabolites
- Urinary niacin metabolite ratio
- Tryptophan when included
- Related B vitamin markers when ordered together
Why people order this test
- Evaluate suspected niacin deficiency
- Investigate skin, digestive, or nervous system symptoms with poor nutrition
- Check B vitamin status in restrictive diets
- Review nutrient status in malabsorption conditions
- Follow up on long-term use of medications that affect niacin
- Assess nutritional status before discussing supplementation
How to prepare
Fasting may be requested depending on the method and whether other tests are included. A blood sample is drawn from a vein, usually at the arm, or a urine sample may be collected. Follow the specific instructions provided with the order.
Understanding your results
Results are typically reported within one to three business days. The report shows the niacin level or metabolite ratio relative to the reference range. A low value suggests deficiency, and a healthcare provider interprets it with diet, symptoms, and other findings.
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Frequently Asked Questions
What is vitamin B3 used for?
Niacin helps convert food into energy and supports the skin, digestive tract, and nervous system.
What are the signs of niacin deficiency?
Deficiency can affect the skin, digestion, and mental function, but these signs have many causes. A healthcare provider evaluates the whole picture.
How is the test performed?
Depending on the laboratory, niacin status may be measured in blood or through urine metabolites.
Do I need to fast before the test?
Fasting may be requested for some methods. Follow the instructions included with your order.
Can too much niacin be a problem?
High intakes, especially from supplements, can cause flushing and other effects. Testing is usually ordered to look at status rather than to guide supplement doses.
Ready to get tested?
Order online and visit a collection site near you, or choose a mail-in kit. No referral and no insurance required.
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