Testing for IgG deficiency involves a combination of several tests, including a complete blood count (CBC), immunoglobulin (Ig) assay, and a specific IgG subclass assay.
The CBC test measures the number of white blood cells, red blood cells, and platelets in a sample of blood. Low IgG levels can lead to anemia, which can be detected by a decrease in the number of red blood cells. A decrease in the number of white blood cells can indicate an impaired immune system, which can be caused by IgG deficiency.
The Ig assay measures the amount of IgA, IgG, IgM, and IgE in a sample of blood, which can help to diagnose IgG deficiency. Low levels of IgG are indicative of a deficiency.
The IgG subclass assay measures the amount of IgG1, IgG2, IgG3, and IgG4 in the blood. Low levels of IgG1 and IgG2 are indicative of a primary IgG deficiency, while low levels of IgG3 and IgG4 are indicative of a secondary IgG deficiency.
In addition to these tests, a doctor may order a physical exam and a thorough medical history to rule out other possible causes of the symptoms. Appropriate treatment for IgG deficiency will depend on the patient’s individual needs. Treatment may include immunoglobulin replacement therapy, antibiotics, or dietary supplements.