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GeneralGamma Gap

Gamma Gap Calculator (Protein Gap)

Calculate the gamma gap from total serum protein and albumin.

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Gamma gap

Calculated protein gap; no universal category is assigned

Equivalent: g/L

About

The gamma gap, also called the protein gap, is total serum protein minus albumin. It is a calculated aggregate of non-albumin proteins, not a directly measured gamma-globulin fraction.

Formula

Gamma gap = total protein − albumin

Interpretation

What the result represents: The calculated concentration of serum proteins other than albumin.

Input units: Total protein and albumin may be entered in g/dL or g/L and are normalized to g/dL.

Worked example: Total protein 7.5 g/dL minus albumin 4.0 g/dL gives 3.5 g/dL.

Applicable population: Laboratory reference use with contemporaneous serum total protein and albumin results.

Interpretation limitations: The gap does not isolate gamma globulins and cannot confirm monoclonal protein, infection, inflammation, or immune disease. Proposed cutoffs have limited sensitivity; use the reporting laboratory context and other tests rather than a universal category.

References

  1. Liu GY, et al. Gamma gap thresholds and HIV, hepatitis C, and monoclonal gammopathy. PLoS One. 2020.
  2. Busher JT. Serum Albumin and Globulin. Clinical Methods. NCBI Bookshelf.

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Disclaimer

Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.