Test Catalog

Test ID: VITB2    
Riboflavin (Vitamin B2), Plasma

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluation of individuals who present the signs of ariboflavinosis

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

There are 3 principle vitamin B2-active flavins found in nature riboflavin, riboflavin 5-phosphate (flavin mononucleotide: FMN), and riboflavin-5'-adenosyl-diphosphate (flavin adenosine dinucleotide: FAD). In biological tissues, FMN and FAD serve as prosthetic units for a large variety of flavoproteins, which are hydrogen carriers in oxidation-reduction processes.


Dietary deficiency of riboflavin (ariboflavinosis) is characterized by sore throat, cheilosis (lesions on the lips), angular stomatitis (lesions on the angles of the mouth), glossitis (fissured and magenta-colored tongue), corneal vascularization, dyssebacia (red, scaly, greasy patches on the nose, eyelids, scrotum, and labia), and normocytic, normochromic anemia. Severe riboflavin deficiency may affect the conversion of vitamin B6 to its coenzyme, as well as conversion of tryptophan to niacin.


Riboflavin has a low level of toxicity and no case of riboflavin toxicity in humans has been reported. The limited absorptivity of riboflavin and its ready excretion in the urine normally preclude a health problem due to increased intake of riboflavin.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Normal: 1-19 mcg/L

Interpretation Provides information to assist in interpretation of the test results

Low concentrations in the blood plasma are indicative of nutritional deficiency. Concentrations below 1 mcg/L are considered significantly diminished. Marginally low levels probably represent nutritional deficiency that should be corrected.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Testing of nonfasting specimens or the use of dietary vitamin B2 supplementation can result in elevated plasma vitamin B2 concentrations.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Russell RM, Suter PM: Vitamin and trace mineral deficiency and excess. In Harrison's Principles of Internal Medicine. 17th edition. Edited by AS Fauci, DL Kasper, E Braunwald, et al. New York, McGraw-Hill Book Company, 2008, pp 441-449

2. Ball GFM: Vitamins: Their role in the human body. Oxford, Blackwell Publishing, 2004, pp 289-299

3. McCormick DB: Riboflavin. In Modern Nutrition in Health and Disease. 10th edition. Edited by ME Shils, M Shike, AC Ross, et al. Philadelphia, Lippincott Williams and Wilkins, 2006, pp 434-441

4. Hustad S, McKinley MC, McNulty H, et al: Riboflavin, flavin mononucleotide, and flavin adenine dinucleotide in human plasma and erythrocytes at baseline and after low-dose riboflavin supplementation. Clin Chem 2002;48:1571-1577

5. Midttun O, Hustad S, Solheim E, et al: Multianalyte quantification of vitamin B6 and B2 species in the nanomolar range in human plasma by liquid chromatography-tandem mass spectrometry. Clin Chem 2005;51:1206-1216

6. Capo-chichi CD, Gueant JL, Lefebvre E, et al: Riboflavin and riboflavin-derived cofactors in adolescent girls with anorexia nervosa. Am J Clin Nutr 1999;69:672-678

7. Roberts NB. Taylor A. Sodi R: Chapter 37: Vitamins and Trace Elements. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Edited by N Rifai, AR Horvath, CT Wittwer. Sixth edition. St. Louis, MO. Elsevier, 2018. pp 639-718