Vitamin B3

Test Code
NTAC


Quest Code
91029


Alias/See Also
Niacin
Vit B3
VB3


CPT Codes
84591

Includes
Nicotinamide and Nicotinic Acid


Preferred Specimen
1 mL frozen serum collected in a light protected red-top tube (no gel)


Minimum Volume
0.5 mL


Other Acceptable Specimens
Frozen plasma collected in a light protected EDTA (lavender-top) tube


Instructions
Pour serum or plasma into amber transport tube (preferred) or transport tube wrapped in aluminum foil to protect from light.


Transport Temperature
Frozen


Specimen Stability
Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 30 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum separator tubes


Methodology
Chromatography/Mass Spectrometry

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Tues, Thurs, Sat; Report available: 2-4 days


Reference Range
Nicotinamide
Nicotinamide is a metabolite of nicotinic acid. Due to the large variability in the metabolism of nicotinic acid, plasma concentrations of this metabolite are variable. In one study, fasting plasma concentrations were reported to be approximately 40 ng/mL. In another study it was reported that the administration of a single 1000 mg of extended-release tablet of nicotinic acid resulted in a mean peak nicotinamide concentration of 400 ng/mL between 5 and 10 hours post dose, decreasing to about 100 ng/mL by 16 hours post dose.

Nicotinic Acid
Due to the large variability in the metabolism of nicotinic acid, the dosing preparation used (immediate-release vs. extended release), and the mg doses used, the serum concentrations may range from less than 20 ng/mL to about 30,000 ng/mL. After oral administration of an immediate-release tablet, peak plasma concentrations occur in 4 to 5 hours. The plasma half-life of nicotinic acid is about one hour. In one study, fasting plasma concentrations were reported to be less than 20 ng/mL. In another study, it was reported that the administration of a single 1000 mg extended-release tablet resulted in mean nicotinic acid concentrations of less than 50 ng/mL.


Clinical Significance
Nicotinic acid occurs naturally in plants and animals and is also added to many foods as a vitamin supplement.


Performing Laboratory
Quest Diagnostics Nichols Institute Valencia
27027 Tourney Road
Valencia, CA 91355-5386


Last Updated: August 13, 2019


The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.