Vitamin B2 or riboflavin deficiency is usually found in individuals that do not consume a diet rich in organ meats, leafy greens and whole grains. It can be seen in the elderly, alcoholics, and those with chronic liver disease and on total parenteral nutrition. Deficiency may be associated with severe lactic acidosis, especially in HIV patients on triple antibiotics. Riboflavin adsorption is decreased in hyperthyroidism.

Collect the sample before breakfast in the morning, before any medications.