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 but powerful blood test ratio that helps evaluate the balance between the two major groups of serum proteins: albumin and globulins. Albumin, produced by the liver, is the most abundant plasma protein and plays critical roles in maintaining oncotic pressure and transporting hormones, drugs, and fatty acids. Globulins encompass a diverse group of proteins including immunoglobulins (antibodies), complement proteins, and 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 clinical interpretation, identifies potential associated conditions, and displays the relative proportion of each protein fraction. The tool is particularly useful for primary care providers interpreting comprehensive metabolic panels and for patients seeking to understand their lab results.
The A/G ratio calculator provides instant interpretation of serum protein results, helping clinicians and patients understand the significance of albumin and globulin levels. It automatically computes globulin from total protein when not directly available and flags patterns associated with serious conditions like multiple myeloma, cirrhosis, and nephrotic syndrome. Keep these notes focused on your operational context. Tie the context to the calculator’s intended domain.
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.
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). Use this as a practical reminder before finalizing the result.
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. Keep this note short and outcome-focused for reuse.
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. Apply this check where your workflow is most sensitive.