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North West London Pathology > Tests > Vitamin A

Vitamin A

Category Biochemistry
Test background

Retinol, the dietary form of vitamin A, is a fat-soluble, antioxidant vitamin important in vision and bone growth. Vitamin A synthesis is achieved through hydrolysis of animal-derived retinyl esters to retinol and, similarly, from pro-vitamin A plant carotenoids. Vitamin A is essential for skin growth, bone formation, immune function and vision. One of the earliest signs of vitamin A deficiency is night-blindness, followed by decreased visual acuity. Excess vitamin A can be hepatotoxic and moderately-elevated chronic levels correspond to increased incidence of osteoporotic events.
Clinical Indications

Suspected deficiency or suspected toxicity/overdose

Reference range
Age (Male and Female) Vitamin A Reference Range (umol/L)
<1 year 0.30 – 1.90
1 year – <11 years 1.00 – 1.60
11 years – <16 years 0.90 – 1.90
16 years – <19 years 1.00 – 2.60
>19 years 1.11 – 2.68

 

 
Sample & container required SST (gold top), serum (red top) or heparin (green top). Samples should be protected from light.
Sample volume 0.5 mL
Turnaround time 2 weeks
Notes

Usually only indicated in case of overdoses or chronic ingestion.

Freeze samples immediately after separation and protect from light.

Samples can be shipped frozen or sent by First class post.

Due to a method change on 28th January 2025, we are not currently accredited for this test. An application for assessment will be submitted.