Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (1295 page)

   Interpretation

Decreased In

   Alcoholism

   Anemia

   Cancer

   Hemodialysis

   Hyperthyroidism

   Malabsorption

   Pregnancy

   Rheumatoid disease

   Scurvy

   Limitations

   Drugs and substances that may decrease vitamin C levels include acetylsalicylic acid, aminopyrine, barbiturates, estrogens, heavy metals, oral contraceptives, nitrosamines, and paraldehyde.

   Chronic tobacco smoking decreases vitamin C levels.

   Testing of nonfasting specimens or the use of vitamin supplementation can result in elevated plasma vitamin concentrations. Reference values were established in patients who were fasting.