What is an immunoglobulins blood test?
This test measures the amount of immunoglobulins, also known as antibodies, in your blood. Antibodies are proteins made by the immune system to fight disease-causing substances, like viruses and bacteria. Your body makes different types of immunoglobulins to fight different types of these substances.
An immunoglobulins test usually measures three specific types of immunoglobulins. They are called igG, igM, and IgA. If your levels of igG, igM, or IgA are too low or too high, it may be a sign of a serious health problem.
Other names: quantitative immunoglobulins, total immunoglobulins, IgG, IgM, IgA testing
IGG Lab Test
An immunoglobulins blood test may be used to help diagnose a variety of conditions, including:
- Bacterial or viral infections
- Immunodeficiency, a condition that reduces the body’s ability to fight infections and other diseases
- An autoimmune disorder, such as rheumatoid arthritis or lupus. An autoimmune disorder causes your immune system to attack healthy cells, tissues, and/or organs by mistake.
- Certain types of cancer, such as multiple myeloma
- Infections in newborns
Why do I need an immunoglobulins blood test?
You may need this test if your health care provider thinks your immunoglobulin levels might be too low or too high.
Symptoms of levels that are too low include:
- Frequent and/or unusual bacterial or viral infections
- Chronic diarrhea
- Sinus infections
- Lung infections
- Family history of immunodeficiency
If your immunoglobulin levels are too high, it may be a sign of an autoimmune disease, a chronic illness, an infection, or a type of cancer. Symptoms of these conditions vary greatly. Your health care provider may use information from your physical exam, medical history, and/or other tests to see if you are at risk for one of these diseases.
Immunoglobulin G, Qn, Serum
The most abundant immunoglobulin in human serum is immunoglobulin G (IgG) (approximately 80% of the total). IgG protein is comprised of molecules of 4 subclasses designated IgG1 through IgG4. Each subclass contains molecules with a structurally unique gamma heavy chain. Of total IgG, approximately 65% is IgG1, 25% is IgG2, 6% is IgG3, and 4% is IgG4. Molecules of different IgG subclasses have somewhat different biologic properties (eg, complement fixing ability and binding to phagocytic cells), which are determined by structural differences in gamma heavy chains. Clinical interest in IgG subclasses concerns potential immunodeficiencies (eg, subclass deficiencies) and IgG4-related diseases (eg, IgG4 elevations). The IgG subclass assay (IGGS / IgG Subclasses, Serum) is best for deficiency testing, and the IgG4 assay (IGGS4 / Immunoglobulin Subclass IgG4, Serum) is best for IgG4-related disease testing.
What does it mean if your Immunoglobulin G, Qn, Serum result is too low?
Diminished concentrations of IgG subclass proteins may occur in the context of hypogammaglobulinemia (eg, in common variable immunodeficiency where all immunoglobulin classes are generally affected) or deficiencies may be selective, usually involving IgG2.
Deficiency of IgG1 usually occurs in patients with severe immunoglobulin deficiency involving other IgG subclasses.
Deficiency of IgG2 is more heterogeneous and can occur as an isolated deficiency or in combination with deficiency of immunoglobulin A (IgA), or of IgA and other IgG subclasses. Most patients with IgG2 deficiency present with recurrent infections, usually sinusitis, otitis, or pulmonary infections. Children with deficiency of IgG2 often have deficient antibody responses to polysaccharide antigens including bacterial antigens associated with Haemophilus influenzae type B and Streptococcus pneumoniae. Isolated deficiencies of IgG3 or IgG4 occur rarely, and the clinical significance of these findings is not clear.
What does it mean if your Immunoglobulin G, Qn, Serum result is too high?
May mean a long-term (chronic) infection, such as AIDS, is present. Levels of IgG are higher in IgG MGUS, IgG multiple myeloma, long-term hepatitis, and multiple sclerosis (MS). In multiple myeloma, tumor cells make only one type of IgG antibody (monoclonal); the other conditions cause an increase in many types of IgG antibodies (polyclonal).
What happens during an immunoglobulins blood test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Will I need to do anything to prepare for the test?
You don’t need any special preparations for an immunoglobulins blood test.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
What do the results mean?
If your results show lower than normal levels of immunoglobulins, it may indicate:
- Kidney disease
- Severe burn injury
- Complications from diabetes
If your results show higher than normal levels of immunoglobulins, it may indicate:
- An autoimmune disease
- A chronic infection
- A viral infection such as HIV or cytomegalovirus
- Multiple myeloma
- Non-Hodgkin lymphoma
If your results are not normal, it doesn’t necessarily mean you have a medical condition needing treatment. The use of certain medicines, alcohol, and recreational drugs can affect your results. If you have questions about your results, talk to your health care provider.
Is there anything else I need to know about an immunglobulins blood test?
Your health care provider may order other tests to help make a diagnosis. These tests might include urinalysis, other blood tests, or a procedure called a spinal tap. During a spinal tap, a health care provider will use a special needle to remove a sample of a clear liquid, called cerebrospinal fluid, from your back.