ascorbate in specimen

Normal range: 1) serum/plasma: 0.4-1.5 mg/dL (23-85 umol/L) -> ascorbate deficiency < 0.2 mg/dL 2) buffy coat: 20-53 ug/10E8 leukocytes (1.14-3.01 fmol/leukocyte) Clinical significance: - leukocyte levels reflect general tissue storage Increases: 1) oral vitamin C supplements will increase plasma levels a) large doses (grams/day) may result in plasma levels > 2 mg/dL b) renal threshold for vitamin C is 1.0 mg/dL (57 umol/L) Decreases: 1) chemical interferences a) plasma -> aminopyrine, aspirin, barbiturates, estrogens, heavy metals, oral contraceptives, nitrosamines, paradehyde b) leukocytes -> tetracycline 2) clinical disorders a) plasma -> scurvy, anemia, pregnancy, steatorrhea, alcoholism, malabsorption, hyperthyroidism, rheumatoid disease, cancer, hemodialysis b) leukocytes* -> scurvy, peptic ulcer, gastroduodenal disorders, post-operative state c) blood levels are lower in males & in heavy smokers * results may be misleading when either leukocyte or platelet count is abnormal Specimen: 1) serum or plasma (oxalate, EDTA or heparin) avoid hemolysis a) deproteinize promptly with metaphosphoric acid (5 g/dL) or trichloroacetic acid (10 g/dL) b) supernatants stable at -20 C for 2 months 2) whole blood (stable for 3 hours refrigerated) 3) buffy coat a) collect whole blood (EDTA or heparin) b) separate buffy coat; avoid erythrocyte contamination c) assay promptly

Related

ascorbate; ascorbic acid; vitamin C buffy coat

Specific

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

References

Clinical Guide to Laboratory Tests, 3rd ed. Teitz ed., W.B. Saunders, 1995