GlobulinSerum globulin · Total globulin

Globulin is not one protein but a group: immunoglobulins (antibodies), transport proteins that carry iron, hormones and copper, and proteins involved in clotting and inflammation. On most reports it is not measured directly but worked out by subtracting albumin from total protein.

It matters because the group is dominated by the immune system, so the figure tends to rise with long-running inflammation or infection and with some blood disorders, and to fall where antibody production is reduced or protein is being lost.

In practice it is read as part of the albumin-to-globulin picture rather than alone, and an unexpected result is followed up with tests that separate the individual protein bands rather than by repeating this one.