IgA
What it measures, and what changes the number.
Immunoglobulin A (IgA) is an antibody class found in blood and, in large amounts, in mucosal secretions such as saliva, tears and the lining of the gut and airways. The blood test measures total IgA in serum, not antibodies against any particular target.
It is usually ordered as part of an immunoglobulin panel with IgG and IgM, and sometimes IgE, to assess antibody production. It is also commonly measured alongside anti-tTG IgA in celiac screening, because that test relies on the body producing IgA and total IgA shows whether the IgA-based result can be relied on.
Fasting is not usually required. It is measured by nephelometry or turbidimetry, and results vary somewhat between methods and with age. Labs may print it as IgA, Immunoglobulin A or Inmunoglobulina A.
Often read alongside: IgG, IgM, IgE, Anti-tTG IgA, Total protein