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Epic Code LAB1230858 Vitamin B3 and Metabolites, Plasma

Additional Codes

Mayo Code: VITB3

Interface Code: 1230858

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Assisting in the diagnosis of suspected vitamin B3 deficiency or toxicity


May be useful in determining response to therapy

Specimen Type

Plasma EDTA

Specimen Required

Patient Preparation: Fasting 4 to 8 hours preferred

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Collection Container/Tube:

Preferred: Lavender top (K2 EDTA)

Acceptable: K3 EDTA

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions: Centrifuge and aliquot plasma into a plastic vial within 2 hours of collection.

Laboratory Test Directory Note:

COLLECTION NOTE: Volumes listed are in serum or plasma, draw approximately 2 1/2 times the requested volume in whole blood.


Specimen Minimum Volume

0.75 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma EDTA Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  21 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus OK

Day(s) Performed

Monday, Tuesday, Thursday, Friday

Reference Values

Nicotinic Acid (Niacin) Cutoff: <5.0 ng/mL

Nicotinamide: 5.0-48.0 ng/mL

Nicotinuric Acid Cutoff: <5.0 ng/mL

Clinical Information

Vitamin B3 is the term used for a group of closely related water-soluble pyridine derivatives, primarily derived from tryptophan. Niacin (also known as nicotinic acid) is converted to nicotinamide, which can also be synthesized directly from tryptophan. Nicotinamide serves as the precursor of nicotinamide-adenine dinucleotide (NAD) and NAD phosphate (NADP), essential coenzymes for numerous dehydrogenases. Many of these enzymes play a role in energy release from carbohydrates and fats, but numerous other pathways are also NAD/NADP dependent, ranging from intra- and inter-cell signaling, to DNA repair, to fatty acid-, cholesterol- and steroid hormone synthesis, and many other vital biochemical functions.


Nicotinuric acid is a major inactive metabolite of niacin and nicotinamide.


Vitamin B3 deficiency most severely impacts tissues with high energy requirements, or high turnover. Thus, skin, the gastrointestinal tract, and the brain are primarily affected, but the function of numerous other organ systems, such as bone marrow and heart, might also be impaired. Severe vitamin B3 deficiency manifests as a distinct clinical syndrome, called pellagra, which is clinically characterized by the "3Ds": dermatitis, diarrhea, and dementia; if untreated, it will result in death.


The onset of deficiency symptoms is subacute or chronic.


The most common cause of vitamin B3 deficiency is inadequate dietary intake of niacin or tryptophan. At-risk populations are older adults, those with limited income, and those who are malnourished or suffer from malabsorption. Malnourished individuals with severe chronic alcoholism are at particularly high risk, as high alcohol intake impairs absorption of niacin and tryptophan as well as further downstream liver metabolism to bioactive of vitamin B3 compounds.


Liver disease in general is also a risk factor, as nicotinamide is derived in the liver from tryptophan. This process requires vitamins B6, B2, and iron, so deficiencies of any of these factors might also predispose the individual to vitamin B3 deficiency.


Issues that impact the availability of tryptophan for vitamin B3 synthesis can also lead to deficiency. Examples include:

-Hartnup disease, a hereditary disorder that reduces tryptophan absorption

-Carcinoid syndrome, a gastro-entero-pancreatic neuroendocrine tumor disorder that results in serotonin overproduction, with the majority of available tryptophan being channeled into serotonin synthesis

-Various drugs (eg, isoniazid, chloramphenicol, fluorouracil, mercaptopurine)


In most cases, vitamin B3 supplementation should result in a cure, even if the deficiency has progressed to the state of pellagra.


Vitamin B3 toxicity is much less common than deficiency. Its occurrence is essentially limited to individuals who consume vitamin B3 supplements in extremely excessive doses, or to patients who are prescribed niacin for treatment of hypercholesterolemia, as the doses used in this setting are very high. Common symptoms are flushing, itching, dizziness, tachycardia, nausea and vomiting, diarrhea, and gout. Rarely liver damage or stroke has been observed. The onset of symptoms is acute or subacute.


Testing of nonfasting specimens can result in elevated plasma vitamin B3 concentrations, particularly in patients with dietary supplement use or patients on niacin treatment.


Nicotinamide concentrations below the established reference range indicate a deficiency.


Niacin or nicotinamide concentrations that exceed the upper reference range substantially suggest potential toxicity in patients with excessive supplement intake or under niacin treatment for hypercholesterinemia.

Reporting Name

Vitamin B3 and Metabolites, P

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Method Description

Vitamin B3 components (nicotinic acid/niacin, nicotinamide, nicotinuric acid) are extracted from plasma specimens with internal standard and then analyzed by liquid chromatography-tandem mass spectrometry.(Unpublished Mayo method)

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
VITB3 Vitamin B3 and Metabolites, P 102102-1


Result ID Test Result Name Result LOINC Value
609493 Nicotinic Acid (Niacin) 18244-4
609494 Nicotinamide 56961-6
609495 Nicotinuric Acid 72306-4

Report Available

2 to 4 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Clinical Reference

1. Delgado-Sanchez L, Godkar D, Niranjan S: Pellagra: rekindling of an old flame. Am J Ther. 2008 Mar-Apr;15(2):173-175. doi: 110.1097/MJT.1090b1013e31815ae31309

2. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA): A Scientific opinion on dietary reference values for niacin. EFSA Journal. 2014;12(7):3759. doi: 10.2903/j.efsa.2014.3759

3. Expert Group on Vitamins and Minerals: Safe Upper Levels for Vitamins and Minerals. Food Standard Agency; 2003:1-361. Accessed January 18, 2022. Available at

4. Fu CS, Swendseid ME, Jacob RA, McKee RW: Biochemical markers for assessment of niacin status in young men: Levels of erythrocyte niacin coenzymes and plasma tryptophan. J Nutr. 1989 Dec;119(12):1949-1955

5. Powers HJ: Current knowledge concerning optimum nutritional status of riboflavin, niacin and pyridoxine. Proc Nutr Soc. 1999 May;58(2):435-440

6. Shah GM, Shah RG, Veillette H, et al: Biochemical assessment of niacin deficiency among carcinoid cancer patients. Am J Gastroenterol. 2005 Oct;100(10): 2307-2314. doi: 2310.1111/j.1572-0241.2005.00268.x

7. Sun WP, Zhai MZ, Li D, et al: Comparison of the effects of nicotinic acid and nicotinamide degradation on plasma betaine and choline levels. Clin Nutr. 2017 Aug;36(4):1136-1142