A/G ratio = albumin ÷ globulin, where globulin = total protein − albumin. A normal ratio is slightly above 1; a ratio below 1 means more globulin than albumin, which calls for a closer look at both proteins. The ratio works in g/dL or g/L because the units cancel.
Enter total protein and albumin from the same blood test. The calculator returns calculated globulin, the A/G ratio and flags against example ranges from Cleveland Clinic, with interpretation from MedlinePlus and the NCBI Bookshelf's Clinical Methods. It's written for clinicians and students; if this is your own result, the flags here are not a diagnosis, and an out-of-range ratio is something to go over with the doctor who ordered the test.
How to use this calculator
- Choose g/dL (US) or g/L (UK, Europe, Australia) with the unit menu.
- Enter total protein and albumin. Albumin must be lower than total protein.
- Read the A/G ratio, then the globulin value and its flag.
- Check each result against the reference range printed on your lab report; our flags are a general guide.
How globulin and the ratio are calculated
- Globulin = total protein − albumin.
- A/G ratio = albumin ÷ globulin.
Clinical Methods puts normal serum total protein at 6–8 g/dL, with albumin 3.5–5.0 g/dL and globulins making up the rest. It names the biuret reaction as the most widely used method for total protein. Globulin is not measured directly on a routine panel but calculated, so any error in total protein or albumin carries into the ratio.
Worked examples
Five typical protein patterns run through the calculator's own functions (all values in g/dL).
| Total protein | Albumin | Globulin | A/G ratio | Reading | Scenario |
|---|---|---|---|---|---|
| 7.2 g/dL | 4.2 g/dL | 3.0 | 1.40 | Within the usual range | Typical adult |
| 8.6 g/dL | 3.6 g/dL | 5.0 | 0.72 | Below 1 (reversed): less albumin than globulin | High globulin (e.g. chronic inflammation) |
| 5.8 g/dL | 2.6 g/dL | 3.2 | 0.81 | Below 1 (reversed): less albumin than globulin | Low albumin (e.g. liver or kidney protein loss) |
| 9.5 g/dL | 3.2 g/dL | 6.3 | 0.51 | Below 1 (reversed): less albumin than globulin | Very high globulin: A/G below 1 |
| 6.2 g/dL | 4.4 g/dL | 1.8 | 2.44 | Within the usual range | Low globulin |
The same A/G ratio can come from very different situations. In row 2 albumin is normal and globulin is high; in row 3 albumin is low. The ratio alone cannot tell them apart, which is why labs report all three numbers.
Ratio for common total protein and albumin values
A/G ratio for common total protein (rows) and albumin (columns) values in g/dL. Ratios below 1 are in bold.
| Total protein ↓ / Albumin → | 3.0 | 3.5 | 4.0 | 4.5 |
|---|---|---|---|---|
| 6.0 | 1.00 | 1.40 | 2.00 | 3.00 |
| 6.5 | 0.86 | 1.17 | 1.60 | 2.25 |
| 7.0 | 0.75 | 1.00 | 1.33 | 1.80 |
| 7.5 | 0.67 | 0.88 | 1.14 | 1.50 |
| 8.0 | 0.60 | 0.78 | 1.00 | 1.29 |
| 8.5 | 0.55 | 0.70 | 0.89 | 1.13 |
Reference ranges
| Test | Range | Source |
|---|---|---|
| Total protein | 6.3–8.0 g/dL | Cleveland Clinic |
| Total protein | 6.5–8.1 g/dL (65–81 g/L) | MedlinePlus |
| Total protein | 60–80 g/L | URMC |
| Albumin | 3.9–4.9 g/dL | Cleveland Clinic |
| Albumin | 3.5–5.0 g/dL | Clinical Methods |
| Albumin | 35–52 g/L | URMC |
| Globulin | 2.0–3.5 g/dL | Cleveland Clinic |
| Globulin (calculated) | 2.2–4.0 g/dL (to 60 y); 2.2–3.7 (over 60) | Beaumont Laboratory |
| A/G ratio | Slightly above 1 | Cleveland Clinic |
The ranges differ because labs use different methods and populations. None is "the" normal range; the one on your report is the one to use.
Low A/G ratio: what it can indicate
- Low albumin: Clinical Methods lists end-stage liver disease, malabsorption and protein-calorie malnutrition (less albumin made) and nephrotic syndrome and severe burns (albumin lost).
- High globulin: MedlinePlus lists infection, inflammatory disease, immune disorders and certain cancers such as multiple myeloma and lymphoma. Clinical Methods notes a broad rise in gamma globulin in chronic infection, connective tissue disease and liver disease, and a narrow spike in myeloma, Waldenström macroglobulinemia, amyloidosis, lymphoma or monoclonal gammopathy.
- MedlinePlus sums up a low A/G ratio as possibly pointing to autoimmune disease such as lupus, liver disease including cirrhosis, or kidney disease.
High A/G ratio: what it can indicate
- Low globulin: MedlinePlus lists liver disease, kidney disease and malnutrition, and for a high A/G ratio mentions certain genetic disorders and leukemia.
- High albumin: Clinical Methods names acute dehydration as the only clinical cause of raised serum albumin. Cleveland Clinic notes dehydration also raises globulin, so a dehydrated patient's ratio may not change much.
Clinical Methods advises that any increase or decrease in the globulin fraction be evaluated with serum protein electrophoresis, which splits globulins into alpha, beta and gamma fractions.
Common mistakes
- Using urine or spot albumin. This calculator is for serum or plasma protein, not the urine albumin-creatinine ratio (ACR).
- Mixing units. Enter total protein and albumin in the same unit. 4.2 g/dL albumin is 42 g/L.
- Reading the ratio alone. Always look at albumin and globulin themselves.
- Ignoring hydration and pregnancy. Cleveland Clinic notes both can shift globulin levels.
- Forgetting albumin elsewhere. Low albumin also lowers the anion gap, so correct it with the anion gap calculator. The BUN/creatinine ratio calculator and corrected sodium calculator cover other parts of the same metabolic panel, and the A1C calculator converts diabetes results.
For healthcare professionals and students only. An A/G ratio is a screening number, not a diagnosis, and this tool offers no medical advice. Interpret it with albumin, globulin, the history and your laboratory's own ranges. Patients should ask their own doctor to explain their results.
Frequently asked questions
What is the A/G ratio?
The albumin/globulin ratio compares the two main groups of blood proteins. Albumin is made by the liver and holds fluid in the blood vessels; globulins include antibodies and transport proteins. MedlinePlus describes the ratio as a comparison of albumin with globulin, reported with a total protein test.
How are globulin and the A/G ratio calculated?
Globulin = total protein − albumin, and A/G = albumin ÷ globulin. Routine panels measure total protein and albumin and calculate globulin (Beaumont Laboratory), so a small error in either measured value carries into both. For total protein 7.2 and albumin 4.2 g/dL: globulin 3.0 g/dL, ratio 4.2 ÷ 3.0 = 1.40.
What is a normal A/G ratio?
Cleveland Clinic says the body typically has slightly more albumin than globulin, so a normal ratio is a little above 1. Using its example ranges (albumin 3.9–4.9, globulin 2.0–3.5 g/dL) gives a range of about 1.11–2.45; this span is our own arithmetic, not a published cut-off. Use the range on your lab report.
What does a low A/G ratio mean?
Either albumin is low, globulin is high, or both. MedlinePlus lists autoimmune disease such as lupus, liver disease including cirrhosis, and kidney disease. A high globulin can also come from chronic infection or multiple myeloma, which is why doctors look at each protein, not just the ratio.
What does a high A/G ratio mean?
Usually that globulin is low. MedlinePlus lists certain genetic disorders and leukemia as possible causes of a high A/G ratio, and low globulin can accompany liver disease, kidney disease or malnutrition. Dehydration raises albumin, the only common cause of high albumin in Clinical Methods.
What does an A/G ratio below 1 mean?
A ratio below 1 means there is more globulin than albumin. It usually reflects a raised globulin, a low albumin or both. Clinical Methods advises that any rise or fall in the globulin fraction should be checked with serum protein electrophoresis.
What is a normal globulin level?
Cleveland Clinic gives 2.0–3.5 g/dL. Beaumont Laboratory reports calculated globulin as 2.2–4.0 g/dL up to age 60 and 2.2–3.7 g/dL over 60. Ranges vary by lab and method.
Does the A/G ratio change if I use g/L instead of g/dL?
No. The ratio has no units, so 72 g/L total protein with 42 g/L albumin gives the same 1.40. Only globulin itself changes unit: 1 g/dL = 10 g/L.
What are the types of globulin?
MedlinePlus names three groups: alpha, beta and gamma globulins. Clinical Methods explains that immunoglobulins (antibodies) mainly run in the gamma region on electrophoresis, and a narrow spike there can point to a monoclonal protein.
Is the A/G ratio part of a CMP?
Yes, many labs report it with a comprehensive metabolic panel or hepatic function panel. Beaumont Laboratory notes the ratio is calculated from total protein and albumin whenever those panels are ordered and cannot be ordered on its own.
Sources & method
- MedlinePlus (US National Library of Medicine) — Total protein and albumin/globulin (A/G) ratio test (what low and high A/G can indicate)
- MedlinePlus — Globulin test (globulin types; causes of low and high globulin)
- MedlinePlus Medical Encyclopedia — Total protein (6.5–8.1 g/dL; causes of high and low levels)
- Clinical Methods, 3rd ed. (NCBI Bookshelf) — Serum albumin and globulin (6–8 g/dL total protein, albumin 3.5–5.0 g/dL, electrophoresis patterns)
- Cleveland Clinic — Globulin blood test (total protein 6.3–8.0, albumin 3.9–4.9, globulin 2.0–3.5 g/dL; A/G slightly above 1)
- Beaumont Laboratory (Corewell Health) test directory — Albumin/globulin ratio and calculated globulin (2.2–4.0 g/dL; 2.2–3.7 over 60)
- University of Rochester Medical Center — Total protein and A/G ratio (60–80 g/L total protein, 35–52 g/L albumin)
Results are estimates for general information. Found an error? It helps everyone — see our methodology.