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24-Hour Vitamin B3 (Niacin) Intake Measurement

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

This test measures how much niacin (vitamin B3) you consumed over a 24-hour period. It helps assess dietary intake of this essential nutrient.

Quick summary

["Understanding your niacin intake can help ensure you meet your daily nutritional needs."]

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

Key facts at a glance

LOINC
81067-1
Short code
Vit B3 intake 24h Measured
Synonyms
Vit B3 intake 24h Measured
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
20
Ref high
400
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
measured
CPT
82670
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

This test quantifies the total niacin consumed from food and supplements over a full day. It does not measure niacin levels in your body but focuses on dietary intake. Niacin is important for metabolism, nerve function, and DNA repair.

Why It Matters in Your Health

Niacin is a water-soluble B vitamin that plays a key role in energy production and maintaining healthy skin, nerves, and digestive systems. Measuring intake helps identify whether you’re getting enough or too much from your diet.

How the Test Works

Your healthcare provider will ask you to record all niacin-containing foods and supplements you consume for 24 hours. You’ll provide a detailed log, and the test measures the total niacin intake based on your report. No blood or urine sample is taken for this test.

What to Expect Before the Test

No special preparation is needed. Simply keep a food diary for the entire day, noting every food or supplement containing niacin. If you’re unsure about a food’s niacin content, you can look it up or ask your doctor.

Reference range

Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Niacin Intake

Frequently asked questions

How might this test result affect my health?
A 24-hour niacin intake test helps determine if your dietary habits align with recommended vitamin B3 intake levels. Low intake may indicate nutritional deficiencies or dietary gaps, while high intake could signal excessive supplementation or dietary choices. Your doctor may use this information to guide dietary advice or further testing if needed.
What does a low niacin intake mean?
A low niacin intake might suggest poor dietary habits, limited exposure to niacin-rich foods (like whole grains, meat, fish, or fortified cereals), or reliance on supplements that don’t fully cover your needs. Your doctor may recommend dietary changes or additional vitamin B3 sources to meet your requirements.
Can I adjust my niacin intake based on this test?
Yes, if your intake is low, your doctor may suggest increasing niacin-rich foods or consulting a dietitian for personalized recommendations. If your intake is high, they may advise monitoring for potential side effects (like flushing or liver concerns) and adjusting as needed.
  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