Vitamin B3

Nicotinic Acid, Niacin (Vitamin B₃), Nicotinamide, Nicotinuric Acid, Niacin, Vitamin B3 and Metabolites, Plasma

Test Codes

EPIC: LAB1232045, Beaker: Vitamin B3, Quest: 91029

NOTE: Testing includes: Nicotinamide and Nicotinic Acid

Department

Send Outs

Specimen Collection Criteria

Collect: One plain Red-top tube.

Do not use Serum Separator Tubes (SST).

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Pour serum or plasma into amber transport tube (preferred) or transport tube wrapped in aluminum foil to protect from light and freeze (-20°C/-4°F or below) prior to transport.

Preparation for Courier Transport

Transport: 1.0 mL light protected serum, frozen (-20°C/-4°F or below). (Minimum: 0.5 mL)

Rejection Criteria

• Serum separator tube (SST).
• Specimens not collected and processed as indicated.

In-Lab Processing

Centrifuge to separate plasma from cells. Pour serum or plasma into amber transport tube (preferred) or transport tube wrapped in aluminum foil to protect from light and freeze (-20°C/-4°F or below) prior to transport.

Transport: 1.0 mL light protected serum, frozen (-20°C/-4°F or below). (Minimum: 0.5 mL) 

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Tuesday, Thursday, Saturday.
Results available in 3-6 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 40.0 ng/mL. In another study it was reported that the administration of a single 1000.0 mg of extended-release tablet of nicotinic acid resulted in a mean peak nicotinamide concentration of 400.0 ng/mL between 5 and 10 hours post dose, decreasing to about 100.0 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 20.0 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 20.0 ng/mL. In another study, it was reported that the administration of a single 1000.0 mg extended-release tablet resulted in mean nicotinic acid concentrations of less than 50.0 ng/mL.

Test Methodology

Chromatography / Mass Spectrometry

Interpretation

By report.

Clinical Utility

This assay provides specific quantitation of a patient's niacin level.

CPT Codes

84591

Contacts

Last Updated

12/19/2025