Specimens no longer need protecting from the light.
Can be measured simultaneously with Vitamin E on the same specimen.
Plasma collected in EDTA, oxalate or citrate is unsuitable.
SST/PST tubes are acceptable, but non-gel tube serum is preferred.
Units: umol/L
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Reference range: 0-6 years 0.7-1.5
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Uncertainty of Measurement:
Vitamin A: 10%
Performed Weekly.
Principle : High performance liquid chromatography with photodiode array detection (HPLC-PDA)
Vitamin A (retinol) is found in fish, liver, meat, and eggs. Beta-carotene is a precursor of vitamin A (provitamin) and is present in green and yellow fruits and vegetables.
Deficiency:
Deficiencies of vitamin A are very rare with an adequate diet. Children are more susceptible than adults. In western countries, vitamin A deficiency is seen primarily among patients with fat malabsorption.
Symptoms of vitamin A deficiency include night-blindness, xerophthalmia progressing to corneal ulceration, and hyperkeratotic skin lesions.
Toxicity:
Acute toxicity of vitamin A has been seen after administration of 150 mg in adults or 100 mg in children. Acute toxicity is manifested by increased intracranial pressure, vertigo, diplopia, bulging fontanels in children, seizures, and exfoliative dermatitis; it may result in death. Chronic vitamin A intoxication may cause dry skin and desquamation, cheilosis, glossitis, vomiting, alopecia, bone pain, hypercalcemia, lymph node enlargement, hyperlipidemia, amenorrhea, and features of pseudotumor cerebri with increased intracranial pressure and papilledema. Liver fibrosis with portal hypertension and bone demineralization may also result from chronic vitamin A intoxication.
References:
1. Tietz Clinical Guide to Laboratory Tests
2. Harrison's Online Ch. 61
Emails to chemicalpathologist@adhb.govt.nz will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours : contact Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Samarina Musaad (Clinical Lead) : SamarinaM@adhb.govt.nz ext. 22402
Dr Cam Kyle: CampbellK@adhb.govt.nz ext 22052
Dr Weldon Chiu: WeldonC@adhb.govt.nz ext. 23427
Dr Campbell Heron: CHeron@adhb.govt.nz ext. 23427
Dr Sakunthala Jayasinghe: Sakunthala@adhb.govt.nz ext. 23427
Aliquot sample
Freeze and transport at -20C