Vitamin C
| Vitamin C | | | |
| Number | | 001479 |
| CPT | | 82180 |
| Synonyms | | Ascorbic Acid ; C, Vitamin |
| Specimen | | Serum, frozen and protected from light; plasma is also acceptable. |
| Volume | | 2 mL |
| Minimum Volume | | 0.7 mL |
| Container | | Red-top tube or gel-barrier tube for serum; lavender-top (EDTA) tube, green-top (heparin) tube, or gray-top (sodium fluoride/potassium oxalate) tube for plasma; amber plastic transport tube with amber stopper. (If amber tubes are unavailable, cover standard transport tube completely, top and bottom, with aluminum foil. Identify specimen with patient name directly on the container and on the outside of the aluminum foil. Secure with tape.) For amber plastic transport tube and amber stopper, order LabCorp No 23598. |
| Collection | | Draw in chilled tube. Separate serum or plasma from cells as soon as possible following collection. Keep specimen on ice. Transfer specimen to a plastic transport tube before freezing. Protect specimen from light. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested. |
| Storage Instructions | | Freeze immediately and protect from light. |
| Causes for Rejection | | Specimen not received frozen; specimen not protected from light |
| Reference Interval | | 0.4-2.0 mg/dL |
| Use | | Evaluation of vitamin C deficiency |
| Methodology | | High-pressure liquid chromatography (HPLC) with electrochemical (EC) detection |
| Additional Information | | 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.1 Low values occur in scurvy, malabsorption, alcoholism, 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 bleeding gums, petechiae, follicular hyperkeratosis, perifollicular hemorrhages beginning on the lower thighs, muscle aches, easy fatiguability, and emotional changes. |
| Footnotes | | - McCormick DB, “Vitamins,” Fundamentals of Clinical Chemistry, 3rd ed, Tietz NW, ed, Philadelphia, PA: WB Saunders Co, 1987, 497-516
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