Table 3.
Differential diagnosis for immunoglobulin levels
| Immunoglobulin | Increased | Decreased |
|---|---|---|
| Ig G | Infection, inflammation, hyperimmunization, IgG multiple myeloma, liver disease, rheumatic fever, systemic rheumatic disease | Agammaglobulinemia, amyloidosis, leukemia, myeloma, preeclampsia |
| IgM | Early HIV infection, infectious mononucleosis, lymphoma, macroglobulinemia, myeloma, rheumatoid arthritis | Rarely agammaglobulinemai, amyloidosis, leukemia, myeloma |
| IgA | Chronic infections (especially of gastrointestinal tract), inflammatory bowel disease, myeloma, rheumatic fever | Agammaglobulinemia, hereditary IgA deficiency, myeloma or protein-losing enteropathy |