Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1291 page)

   
Normal range:
3–15 μg/L.

   Marginally low: 2 μg/L

   Diminished: <2 μg/L

   Use

   Evaluation of persons who present the signs of ariboflavinosis

   Detect riboflavin deficiency

   Interpretation

Decreased In

   Patients with anorexia nervosa

   Individuals who avoid dairy products (such as people with lactose intolerance) because dairy products are a good source of riboflavin

   Patients with malabsorptive syndromes such as celiac sprue, malignancies, and short bowel syndrome

   Rare inborn errors of metabolism in which there is a defect in riboflavin synthesis

   Long-term use of phenobarbital and other barbiturates, which may lead to oxidation of riboflavin and impair its function

   Limitations

   Testing of nonfasting specimens or the use of dietary vitamin B
₂
supplementation can result in elevated plasma vitamin B
₂
concentrations.