Vitamin A optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Vitamin A:

Optimal 30 – 60 μg/dL (1.05 – 2.09 μmol/L); sufficient 20 – 80 μg/dL (0.7 – 2.79 μmol/L); out of range below 20 or above 80 μg/dL.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

Unit	Optimal	Sufficient	Out of range
μg/dL	30 – 60	20 – 80	below 20 or above 80
μmol/L	1.05 – 2.09	0.7 – 2.79	below 0.7 or above 2.79
μg/mL	0.3 – 0.6	0.2 – 0.8	below 0.2 or above 0.8

What the evidence says

The acceptable band starts at 20 μg/dL (0.70 μmol/L), the level at or below which NIH and WHO place vitamin A deficiency, and ends near the top of the Mayo Clinic Laboratories adult reference interval (78 μg/dL). There is no widely accepted serum level that marks toxicity. The narrower optimal band has no outcome evidence behind it. Insensitive to depletion by design of the physiology: the liver holds most of the body's vitamin A and defends the blood level, so retinol stays normal through a long decline and falls only near exhaustion. It also drops during any acute-phase response, so a low retinol with a raised CRP usually reflects inflammation rather than status.

Sources

Vitamin A and Carotenoids - Health Professional Fact Sheet — NIH Office of Dietary Supplements, 2025 · Government / public-health guidanceA serum or plasma retinol of 20 mcg/dL (0.70 micromol/L) or less frequently reflects moderate deficiency and 10 mcg/dL or less severe deficiency. Matches Sera's sufficient lower edge exactly. Updated March 10, 2025.
VITA - Vitamin A, Serum: Clinical & Interpretive — Mayo Clinic Laboratories, 2026 · Laboratory / reference-interval sourceAdult reference values 32.5 to 78.0 mcg/dL; WHO recommends supplementation below 20.0 mcg/dL; no widely accepted serum level associated with toxicity. Close to Sera's sufficient upper edge of 80 and optimal lower edge of 30.
Vitamin A — Labcorp, 2026 · Laboratory / reference-interval sourceAge-banded adult intervals: 18.9 to 57.3 μg/dL at 20 to 39 years, 20.1 to 62.0 at 40 to 59, 22.0 to 69.5 over 59. The lower limits sit at Sera's sufficient lower edge of 20; the upper limits bracket Sera's optimal upper edge of 60.

What Vitamin A (Retinol) measures

The circulating form of vitamin A, essential for vision, epithelial integrity and immune function.

A poor measure of stores until they are nearly exhausted: the liver holds most of the body's vitamin A and defends the blood level, so retinol stays normal through a long decline and only falls late. It also drops during any acute-phase response independently of status, so a low value alongside a raised CRP usually reflects inflammation rather than deficiency.

Related vitamins & minerals markers

See Vitamin A in the full list of biomarker ranges

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.