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. |
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| Clinical Indications |
Suspected toxicity/overdose Suspected deficiency |
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| Reference range |
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| Sample & container required | SST (gold top), serum (red top) or heparin (green top) Referring laboratories see Notes for sample processing requirements | ||||
| 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 |