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Vitamin B3 (24 hr urine)

Alternative Names:Niacin
nicotinic acid
Laboratory:Clinical Biochemistry
Test Code:B3
Specimen Types:Urine 24 hour
Container Types:
Urine Bottle ACID
Adults Volume or Mass:10 mL
Minimum/Paediatric Volume or Mass:10 mL
Transport Instructions between Sites and/or Laboratories:On Ice
Assay Frequency:Monthly
External Laboratory:Sydney South West Path (SSWPS) - RPA
Additional Notes:

Must be approved by a Chemical Pathologist.

Reference Interval

Vitamin B3 - MCP = 25 - 110 µmol/day

Vitamin B3 - NMN = 10 - 75 µmol/day

MCP/NMN Ratio

INTERPRETIVE COMMENT: Reference Range: Ratio 1.3 to 4

Pellagra is characterised by a deficiency of niacin (Vitamin B3). The ratio of MCP (N1-methyl-2-pyridone-5-carboxylamide) to NMN (N1-methylnicotinamide) is regarded as an important index of niacin status. De Lange and Joubert (Amer J Clin Nutr 1964;15:169-174) defined a MCP to NMN ratio of 1.3 to 4 as normal, and <1.0 as indicative of latent niacin deficiency.

Interpretive comment reviewed March 2013 

HPLC-UV method