A/G ratio 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 A/G ratio:
- Optimal 1 – 2.4; out of range below 1 or above 2.4.
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 |
|---|---|---|---|
| ratio | 1 – 2.4 | — | below 1 or above 2.4 |
No separate Sufficient band is currently defined for this marker.
What the evidence says
The A/G ratio is albumin divided by globulin, where globulin is usually total protein minus albumin. No guideline sets a value: each laboratory establishes its own interval. A chemistry-panel ratio is typically read against about 1.0 to 2.4. A ratio calculated from protein electrophoresis measures albumin differently and carries its own interval, which varies widely between laboratories (0.7 to 2.0 and 0.88 to 2.30 in two US laboratories; some European reports print a narrower range), so read an electrophoresis ratio against the range printed on the report. A low ratio means low albumin, raised globulins or both, and is the direction that matters; a high ratio has no established meaning on its own. There is no evidence for a narrower optimal range.
Sources
- Albumin/Globulin Ratio (AGR) — University of Washington Department of Laboratory Medicine and Pathology, 2026 · Laboratory / reference-interval sourceChemistry-panel A/G ratio with a reference range of 1.0 to 2.4 for both sexes. Sera's proposed 1.1 to 2.5 sits 0.1 higher at each end.
- Protein Electrophoresis, Serum — University of Michigan, MLabs, 2026 · Laboratory / reference-interval sourceCapillary electrophoresis: albumin/globulin ratio 0.88 to 2.30. An electrophoresis-derived ratio here has a lower floor than Sera's proposed 1.1 and a lower ceiling than 2.5.
- Protein Electrophoresis — University of Florida Health Pathology Laboratories, 2026 · Laboratory / reference-interval sourceCapillary electrophoresis: A:G ratio 0.7 to 2.0. This is a second electrophoresis-derived interval, and it differs from Michigan's, from the chemistry interval and from Sera's proposed band.
- The Importance of Verifying Reference Intervals for Calculated Results (JALM Talk) — Association for Diagnostics and Laboratory Medicine — Journal of Applied Laboratory Medicine, 2017 · Professional societyStates that no guideline-based values exist for the A/G ratio, that each laboratory must establish its own interval, and that a change of albumin method changes the interval. It gives no numbers.
What A/G Ratio (Albumin/Globulin) measures
Albumin divided by the globulins: one number for the balance between the protein the liver makes most of and the proteins of the immune system.
It moves for two unrelated reasons, so it only ever points at which of the two to look at. A low ratio means either albumin has fallen (liver disease, protein loss through the kidneys or gut, long inflammation) or the globulins have risen (chronic infection, autoimmune disease, a paraprotein). Read albumin and the globulin fractions themselves before the ratio. A ratio printed on an electrophoresis report is worked from the albumin fraction of the trace and can differ slightly from one worked from a chemistry panel.