ascorbate in specimen

Reference interval

• serum/plasma: 0.4-1.5 mg/dL (23-85 umol/L)
  • ascorbate deficiency < 0.2 mg/dL
• buffy coat: 20-53 ug/10E8 leukocytes (1.14-3.01 fmol/leukocyte)

Clinical significance

• leukocyte levels reflect general tissue storage

Increases

• oral vitamin C supplements will increase plasma levels
  • large doses (grams/day) may result in plasma levels > 2 mg/dL
  • renal threshold for vitamin C is 1.0 mg/dL (57 umol/L)

Decreases

• chemical interferences
  • plasma
    • aminopyrine, aspirin, barbiturates, estrogens, heavy metals, oral contraceptives, nitrosamines, paradehyde
  • leukocytes -> tetracycline
• clinical disorders
  • plasma
    • scurvy, anemia, pregnancy, steatorrhea, alcoholism, malabsorption, hyperthyroidism, rheumatoid disease, cancer, hemodialysis
  • leukocytes*
    • scurvy, peptic ulcer, gastroduodenal disorders, post-operative state
  • blood levels are lower in males & in heavy smokers

* results may be misleading when either leukocyte or platelet count is abnormal

Specimen

• serum or plasma (oxalate, EDTA or heparin) avoid hemolysis
  • deproteinize promptly with metaphosphoric acid (5 g/dL) or trichloroacetic acid (10 g/dL)
  • supernatants stable at -20 C for 2 months
• whole blood (stable for 3 hours refrigerated)
• buffy coat
  • collect whole blood (EDTA or heparin)
  • separate buffy coat; avoid erythrocyte contamination
  • assay promptly

More general terms

• special chemistry test

More specific terms

• ascorbate in blood
• ascorbate in leukocytes
• ascorbate in semen
• ascorbate in serum/plasma
• ascorbate in urine

Additional terms

• ascorbate; ascorbic acid; vitamin C
• buffy coat