Also known as: Ascorbic Acid, C, Vitamin.

Serum or plasma levels of vitamin C are an adequate measurement of clinical status. Vitamin C is a cofactor for protocollagen hydroxylase; it promotes the conversion of tropocollagen to collagen. Low values occur in malabsorption, alcoholism, scurvy, pregnancy, hyperthyroidism, and renal failure. Smokers have lower levels than nonsmokers. Patients with scurvy have values <0.2 mg/dL. Principal clinical findings in scurvy include petechiae, bleeding gums, follicular hyperkeratosis, perifollicular hemorrhages beginning on the lower thighs, muscle aches, easy fatiguability, and emotional changes.