OVERVIEW
What are immunoglobulins?
Immunoglobulins are antibodies which are released in the body by immune system during invasion of foreign particles (antigens) like bacteria, virus, or allergens in the body. Antibodies aid us against various infections. Immunoglobulins are of different types namely IgA, IgG, IgM, IgE, IgD. IgA antibody found in respiratory tract & digestive system lining as well as in tears, saliva, & breast milk. IgG release after an infection or immunization and stay for lifetime. IgM mainly found in lymph fluid & blood, first appears when a new infection occurs. Our body produces different antibodies/immunoglobulins against different things like antibody for chickenpox and antibody for mononucleosis is not the same.
What is immunoglobulin lab test?
This test is indicated for measuring IgA, IgG & IgM antibody levels in the blood, CSF, saliva or other body fluids.
Why is immunoglobulin lab test done?
The test is done:
- As different immunoglobin level detection helps in diagnosing an infection
- As it checks if a person is immune to getting an infection (protected from)
- As it helps diagnose immunodeficiencies (immune system not working)
- When doctor suspects a child or individual who has a lot of infections or unusual infections
- As a part of allergy evaluation
- For evaluation of autoimmune (autoantibodies released) conditions like celiac disease, lupus etc.
- What appears first IgG or IgM?
IgG appears in body fluids after an infection or immunization. While IgM found in blood and lymph fluid appears firstly when the body fights a new infection.
- What is negative diagnosis?
It means that for whatever reason the test was indicated/ performed, it was unable to find that component in the sample.
- What does high IgG levels indicate?
They indicate that the patient has long-term (chronic) infection like in HIV, multiple myeloma, multiple sclerosis, long term hepatitis (liver inflammation)
- What is normal IgG, IgM & IgA levels?
Normal adult range of IgG antibody is 6.0 - 16.0g/L, IgA is 0.8 - 3.0g/L, & IgM is 0.4 - 2.5g/L.
- Does IgM indicate acute or chronic infection?
When IgM is prevalent in the test, it means that infection is acute, whereas if IgG predominates, it means infection is chronic.
INTERPRETATION OF THE RESULTS:
Number of diseases can be associated with decreased or increased immunoglobulins.
- INCREASED IMMUNOGLOBULINS:
- Polyclonal increase in any or all of 3 classes of IgA, IgG &/or IgM:
Indicates towards conditions like infections (acute and chronic), autoimmune disorders (rheumatoid arthritis, systemic lupus erythematosus, scleroderma), cirrhosis (liver condition), chronic inflammation, inflammatory disorders, hyperimmunization reactions, & in a newborn infection during pregnancy (congenital—syphilis, toxoplasmosis, rubella, CMV)
- Monoclonal increase in 1 class with or without decrease in other two classes:
Indicates towards multiple myeloma, chronic lymphocytic leukemia (CLL), MGUS (monoclonal gammopathy of undetermined significance), lymphoma etc.
- DECREASED IMMUNOGLOBULINS:
- Due to condition/factors which affect antibody production:
Like medicines such as phenytoin, carbamazepine, immunosuppressant drugs; complications from conditions such as kidney failure or diabetes; transient delay in production in newborns particularly in premature infants.
- Due to conditions causing an abnormal protein loss:
Like nephrotic syndrome (kidney disease in which protein is lost in the urine), burns, protein-losing enteropathy (any condition of the gastrointestinal tract (GIT) that affects the digestion or absorption of protein)
You get tested for diagnosis of various infections like viral, bacterial, allergy or autoimmune disorders. It is not exactly a diagnostic test but is a strong indicator of disease or conditions.
