Test Contains (LOINC)
Vitamin A (Retinol) (2923-1), Vitamin A Ser/Pla - Interpretation (48767-8), Vitamin A (Retinyl Palmitate) (38496-6)
Serum or Plasma
Sodium or Lithium Heparin (Green), Plasma Separator Tube, or Serum Separator Tube
EDTA (Lavender Top) Tube
Minimal Sample Volume
Patient should fast for 12 hours and abstain from alcohol for 24 hours prior to collection. Separate serum or plasma within 1 hour of collection. Transfer 1 mL serum or plasma to a Standard Transport Tube immediately. (Min: 0.2 mL) Avoid hemolysis.
Client Transport Temperature
After separation from cells: Ambient: Unacceptable; Refrigerated: 1 month; Frozen: 1 year
Whole blood or body fluids other than serum or plasma.
Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
Expected Turn Around
2 - 5 Days
Quantitative High Performance Liquid Chromatography
Serum retinol is typically maintained until hepatic stores are almost depleted. Values greater than 0.30 mg/L represent adequate liver stores, whereas values less than 0.10 mg/L indicate deficiency. Samples that come in contact with plastic tubing or have been exposed to excessive light may show low results.
Vitamin A toxicity occurs when retinol concentration exceeds the capacity of retinol binding protein (RBP). Individuals with compromised renal function can retain RBP and may, therefore, have moderate retinol elevations. Drugs which interfere with vitamin A analysis include probucol (Lorelco).
This assay does not measure other vitamin A metabolites such as retinaldehyde and retinoic acid.