|
Overview :
Results of the relative dose response, in the absence of
malabsorption or with intravenous dosing, correlate with vitamin A stores and
with dark adaptation.
Dose given: retinyl palmitate, either 1 mg as water miscible
solution IV over 30 minutes or 0.45 mg in corn oil given po.
relative dose response, as percentage =
= 100% ( 1 - ((plasma vitamin A prior to dose) / (plasma
vitamin A 5 hrs after dose)))
where:
• Vitamin A is expressed in µg/dL in conventional units
(µmol/L for SIU)
Interpretation:
• The normal relative dose response is < 10%.
• Values > 15% indicate depleted liver vitamin A stores.
• Decreased
levels are seen with: malabsorption, cirrhosis, chronic cholestasis,
hepatocellular disease, protein-caloric malnutrition, zinc deficiency.
|