Calculate the A/G ratio from serum albumin and globulin or total protein values. Includes interpretation guide and associated conditions.
The albumin/globulin (A/G) ratio is a simple blood-test ratio that helps describe the balance between the two main groups of serum proteins: albumin and globulins. Albumin, produced by the liver, is the most abundant plasma protein and contributes to oncotic pressure and transport functions. Globulins include immunoglobulins, complement proteins, and other transport proteins.
A normal A/G ratio typically falls between 1.2 and 2.0. When the ratio is low (below 1.0), it suggests either decreased albumin production, increased albumin loss, or overproduction of globulins. This pattern is seen in conditions such as liver cirrhosis, nephrotic syndrome, malnutrition, chronic infections, and plasma cell disorders like multiple myeloma. Conversely, a high A/G ratio may indicate underproduction of globulins, as seen in certain immunodeficiency states.
This calculator computes the A/G ratio from serum albumin and globulin values, or derives globulin from total protein when globulin is not directly reported. It provides a structured interpretation and shows the relative proportion of each protein fraction, but the ratio is still only one clue within a larger liver, kidney, inflammatory, and hematology workup.
The A/G ratio calculator turns albumin and globulin values into a quick signal about whether protein balance looks more consistent with low albumin production, protein loss, or globulin excess. It also derives globulin from total protein when needed, which makes the result easier to interpret when the lab report does not list the components separately.
A/G Ratio = Serum Albumin (g/dL) ÷ Serum Globulin (g/dL). Globulin = Total Protein − Albumin. Normal albumin: 3.5–5.0 g/dL. Normal globulin: 2.0–4.0 g/dL. Normal A/G ratio: 1.2–2.0.
Result: A/G Ratio = 0.56 — Low ratio, evaluate for cirrhosis, myeloma, or nephrotic syndrome
With albumin of 2.5 g/dL (low) and globulin of 4.5 g/dL (elevated), the A/G ratio is 2.5 ÷ 4.5 = 0.56. This low ratio combined with hypoalbuminemia suggests possible liver disease, nephrotic syndrome, or a plasma cell disorder.
Albumin constitutes approximately 55–65% of total serum protein and is synthesized exclusively by the liver at a rate of about 10–15 g/day. Its half-life is approximately 20 days, making it a better marker of chronic rather than acute nutritional or liver status. Albumin maintains plasma oncotic pressure (preventing edema), binds and transports numerous substances, and serves as a buffer for pH regulation.
Globulins are subdivided into alpha-1, alpha-2, beta, and gamma fractions (identified by serum protein electrophoresis). Alpha and beta globulins include transport proteins like transferrin, ceruloplasmin, and haptoglobin, as well as complement factors. Gamma globulins are primarily immunoglobulins (IgG, IgA, IgM, IgD, IgE) produced by plasma cells. An isolated spike in the gamma region (M-spike) on electrophoresis raises concern for multiple myeloma.
The A/G ratio provides a quick snapshot of the overall protein landscape. While individual protein values are important, the ratio captures the balance between production, loss, and consumption of the two major protein groups. In clinical practice, a persistently abnormal ratio often triggers more specific testing to identify the underlying cause.
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This page divides serum albumin by serum globulin to produce the albumin/globulin ratio. When globulin is not entered directly, it derives globulin from total protein minus albumin. The output then compares the result with broad interpretation bands and shows the relative share of albumin and globulin in total protein.
The ratio is presented as a laboratory clue, not a stand-alone diagnosis. A low or high A/G ratio needs to be interpreted with the rest of the chemistry panel, liver function tests, urinalysis, inflammatory context, and sometimes protein electrophoresis.
A normal A/G ratio is between 1.2 and 2.0. Ratios below 1.0 are generally considered clinically significant and warrant further investigation.
A low ratio can result from decreased albumin (liver disease, malnutrition, nephrotic syndrome) or increased globulins (multiple myeloma, chronic infections, autoimmune diseases, cirrhosis).
An elevated A/G ratio (>2.0) is less common and may indicate immunodeficiency, certain genetic conditions, or dehydration causing relative hemoconcentration.
Yes, it is typically calculated automatically as part of a Comprehensive Metabolic Panel (CMP) or when a total protein test is ordered.
Yes. Dehydration causes hemoconcentration, which can falsely elevate both albumin and globulin levels. The ratio itself may remain relatively stable, but individual values appear higher.
Depending on the pattern, follow-up may include serum protein electrophoresis (SPEP), liver function tests, urinalysis for proteinuria, renal function tests, or immunoglobulin levels.