Vitamin B3 : 1016270

Message
Crtical frozen.

Test Code
VITB3Q or 1016270

Alias/See Also
Niacin

CPT Codes
84591

Instructions
Plain red top tube or lavender (EDTA) top tube.

Transport Container
Centrifuge tube as soon as possible and aliquot 2 mL serum or plasma into a standard transport tube (Min: 1 mL). Freeze immediately.

Transport Temperature
Frozen.

Specimen Stability
Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 30 days

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

Methodology
LChromatography/Mass Spectrometry

Setup Schedule
Tuesday & Thursday & Saturday

Report Available
2-4 days (From receipt at performing laboratory)

Reference Range
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 <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 <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 <50 ng/mL.
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 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.

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



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.