4 - 10 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Serum or plasma
1.5 mL each tube
1 mL each tube (Note: This volume does not allow for repeat testing.)
Red-top tube or lavender-top (EDTA) tube
Transfer the serum into a LabCorp PP transpak frozen purple tube with screw cap (LabCorp N° 049482). The specimen should be frozen immediately and maintained frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen specimens, please submit separate frozen specimen for each test requested. Include the patient's age on the test request form.
Gel-barrier tube; specimen not frozen
Measurement of vitamin B3 level as nicotinic acid and nicotinamide.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
• Nicotinic acid: 0.0−5.0 ng/mL
• Nicotinamide: 5.2−72.1 ng/mL
Niacin (nicotinic acid) is a water-soluble vitamin that is also referred to as vitamin B3.1,2 Nicotinamide (nicotinic acid amide) is the derivative of niacin that is incorporated into the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).1-3 The nicotinamide moiety of NAD and NADP serves as an electron acceptor or donor in biological oxidation-reduction (redox) reactions catalyzed by several hundred different enzymes. NAD serves as the cofactor for enzymes that break down (catabolize) carbohydrates, fats, proteins, and alcohol while NADP supports biosynthetic (anabolic) reactions, including the synthesis of all macromolecules, such as fatty acids and cholesterol.1,2 Nicotinamide has also been shown to serve as a cofactor in adenosine diphosphate (ADP)-ribose transfer reactions that play an integral part in deoxyribonucleic acid (DNA) repair calcium mobilization.3,4 Studies of cultured cells and animal models suggest that ADP-ribose polymer-mediated DNA repair and cyclic ADP-ribose-mediated cell-signaling pathway may play a role in cancer prevention.3,4
Both nicotinic acid and nicotinamide are absorbed from the normal diet. Nicotinamide is the form of vitamin B3 that is commonly found in nutritional supplements and used to fortify foods.1,5 Nicotinic acid is available both over the counter and with a prescription as a cholesterol-lowering agent.6-8 Niacin deficiency can result from inadequate dietary intake of niacin and/or the amino acid tryptophan. Tryptophan, obtained from the breakdown of dietary protein, can be converted to nicotinamide by liver enzymes that require vitamin B6, riboflavin, and iron. Deficiencies of these constituents can contribute to the development of niacin deficiency.1,2 Hartnup's disease, a hereditary disorder that reduces tryptophan absorption, can lead to niacin deficiency.1 Carcinoid syndrome diverts tryptophan to the increased production of serotonin and can reduce the production of nicotinamide.1 Prolonged treatment with isoniazid has also been associated with niacin deficiency.1
Niacin deficiency can affect the skin, digestive system, and the nervous system.1,2 Severe niacin deficiency, referred to as pellagra, has been associated with the "four Ds": dermatitis, diarrhea, dementia, and ultimately death.2 Pellagra dermatitis is characterized by a thick, scaly, darkly pigmented rash that develops symmetrically in areas exposed to sunlight.2 Digestive system symptoms include vomiting, constipation or diarrhea, and a bright red tongue.1,2 Pellagra can also cause neurologic symptoms, including apathy, fatigue, depression, headache, disorientation, and memory loss.1,2
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|070115||Vitamin B3 (Niacin+Metabolite)||070112||Nicotinamide||ng/mL||56961-6|
|070115||Vitamin B3 (Niacin+Metabolite)||070113||Nicotinic Acid||ng/mL||18244-4|
© 2021 Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.
The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf