Vitamin A (retinol): normal blood levels in adults and children, low and high

In shortNormal vitamin A (retinol) in blood of adults is 0.3–0.8 mg/L (0.3–0.8 µg/mL). Deficiency shows as dry skin and night blindness; excess is toxic, especially in pregnancy. The test is taken fasting; the level depends on liver stores.

What this marker is

Vitamin A is a fat-soluble vitamin needed for vision (night vision first), skin, mucosa and immunity. The main reserves are stored in the liver, so blood reflects deficiency late — when the depot is already depleted.

Deficiency occurs with impaired fat absorption (GI and biliary diseases) and poor diet. Excess — from uncontrolled supplements: the vitamin accumulates and is toxic, and teratogenic in pregnancy.

Reference ranges

Group	Reference range
Adults	0.3–0.8 mg/L (0.3–0.8 µg/mL)
Children	0.2–0.6 mg/L — roughly, per the lab report

Blood lags behind the stores: the level holds until the liver is depleted. A low result with a normal diet is a reason to assess fat absorption. Ranges differ between laboratories.

Check your value

Enter the number from your lab report — see how it compares with the typical range. Mind the units shown in the chosen row.

An approximate comparison with a typical range, not a diagnosis. Ranges differ between laboratories — use the one on your report; a doctor interprets the result.

Units and conversion

Measured in: µmol/L

µmol/L=µg/dL

µg/dL = µmol/L × 28.65 (retinol, molar mass 286.5)

When it is high or appears: possible causes

Excess supplementsLong-term high-dose retinol — toxicity: headache, dry skin, bone pain.

Liver diseaseThe vitamin depot is the liver; its diseases shift the level both ways.

When it is low: possible causes

Impaired fat absorptionCeliac disease, biliary disease, after GI surgery — the fat-soluble vitamin is not absorbed.

Poor dietLittle liver, eggs and orange vegetables in the ration.

Increased needsPregnancy, lactation, rapid growth.

What can skew the result

These factors can shift the result without any disease — keep them in mind before a retest:

Retinol-containing supplementsGI and biliary diseaseIsotretinoin intakeStrict diets

How to prepare

In the morning, fasting (8–12 hours), venous blood. Biotin (vitamin B7) in multivitamins can distort some immunoassays — tell the doctor about supplements. Details: Preparation: venous blood.

When a retest makes sense

Deficiency is confirmed by a repeat test in 2–4 weeks; monitoring during supplements is set by the doctor, usually at 8–12 weeks.

Who usually reviews this result

An out-of-range result is usually reviewed by: Primary care physician, gastroenterologist. Bring your report and any previous results to the visit.

Names used on lab reports

Look for one of these names on your report:
Vitamin ARetinolRetinol

Several markers on your report?

The app reads your whole report — this marker together with its neighbors, not one by one.

Get your results explained See an example

Frequently asked questions

Low vitamin A — how to raise it?

First the cause: if absorption is fine, adjust the diet (liver, eggs, carrots, pumpkin) or take a preparation with level control. Self-prescribed high doses are toxic.

Can vitamin A be tested in pregnancy?

Yes, but the doctor interprets: excess retinol is teratogenic, so supplements are taken in pregnancy only as prescribed.

Dry skin and poor night vision — a deficiency?

Classic signs, but not only of vitamin A deficiency. The test together with a doctor’s exam answers more precisely.

Sources

MedlinePlus — Vitamin A test — MedlinePlus (medlineplus.gov). Accessed: September 17, 2026.
MedlinePlus — Vitamin A test — MedlinePlus (medlineplus.gov). Accessed: September 17, 2026.

Vitamin A (retinol)