The immunoglobulin test measures the level of different antibodies in the blood. The immune system produces antibodies to help protect the body from foreign substances such as allergens, viruses and bacteria.
The body produces different immunoglobulins, also known as antibodies, to protect the body. For example, the body produces a different antibody for chickenpox and another type of antibody for mononucleosis. Sometimes, the body mistakenly produces antibodies against itself, which treat healthy tissues and organs as foreign invaders. This is known as an autoimmune disease.
The body produces a few different types of immunoglobulin, including:
These antibodies are in the mucous membrane of the intestines, lungs, stomach and sinuses. IgA is also present in fluids these membranes produce, such as tears, saliva and blood.
IgG is the most common antibody in the blood and other fluids in the body. They offer protection against infection by identifying germs you have previously contracted with the germ. If you get reinfected by those germs, your immune system knows to attack them.
Your doctor can order a test for IgG to determine if certain viruses or bacteria have infected you.
The body produces IgM antibodies following a first infection from a new bacteria or other germs. They are the first defence mechanism against infections in the body. When your body first encounters an invader, your IgM levels will rise for a short period, then gradually drop as your IgG levels are produced and increase to offer long-term production.
The body produces IgE antibodies during reactions to harmful substances such as pet dander or pollen. A blood test for allergies can measure your IgE levels.
Your doctor may order immunoglobulin testing if you have infections, especially infections of the stomach, lungs, sinuses or intestines. Your doctor may also order the test if you have:
Kids can drink and eat normally, except that they also need other tests that require fasting. Inform your doctor about any medicines your child takes, as some medications may affect the test result.
Wearing a short-sleeved shirt or T-shirt for this test can make the blood sample collection easier for your child. You may also bring along a book or toy for distraction.
Like most blood tests, the immunoglobulin blood test involves taking a small amount of blood from the vein. To collect the blood sample, the healthcare provider will:
In some cases, immunoglobulin tests use a fingerprick test. The healthcare provider will clean your finger, then prick the tip of the finger with a small needle (lancet) to collect a small blood sample
Blood sample collection only causes temporary discomfort, usually like a quick pinprick.
The test results for IgM, IgA and IgG are usually together. Abnormal test results indicate a problem with the immune system and will need further testing. Immunoglobulin testing isn’t a diagnostic test but offers information that a condition or disease is present. Several conditions can increase or decrease immunoglobulins.
Elevated polyclonal immunoglobulins may result from different conditions, while monoclonal immunoglobulins occur from blood cell tumours involving plasma cells or lymphocytes. These disorders usually cause an increase in a type of immunoglobulin and a decrease in the other two classes.
Although some people with this condition may have a high total immunoglobulin level, they are immunocompromised because most of the immunoglobulin produced is abnormal and has no role in the immune response.
The table below gives some conditions that can increase immunoglobulin.
|Polyclonal increase in one or all three classes (IgM, IgG and IgA)
· Autoimmune disorders (lupus, rheumatoid arthritis, scleroderma)
· Chronic inflammation
· Wiskott-Adrich syndrome
· Chronic and acute infections
· Infection during pregnancy in a newborn (CMV, rubella, syphilis, toxoplasmosis)
· Hyperimmunisation reactions
|Monoclonal increase in a close with or without reduction in the other two classes
· Multiple myeloma
· MGUS (monoclonal gammopathy of undetermined significance)
· Waldenstrom’s macroglobulinemia (IgM)
· Chronic lymphocytic leukaemia
Acquired underlying conditions that increase protein loss from the body or affect the body’s ability to produce immunoglobulins are the most common causes of low immunoglobulin levels.
Immunoglobulin deficiencies may also result from drugs such as phenytoin, carbamazepine, corticosteroids, or from toxins.
The table below shows the common causes of low immunoglobulin levels.
|Factors or conditions that affect immunoglobulin production
· Transient hypogammaglobulinemia of infancy (transient delay in production in newborns, especially in premature infection)
· Complications from conditions like diabetes or kidney failure
· Drugs such as carbamazepine, phenytoin and immunosuppressant drugs
|Conditions causing abnormal protein loss
· Nephrotic syndrome – kidney disease where the protein gets lost in the urine
· Protein-losing enteropathy – any gastrointestinal tract condition that affects absorption or digestion of protein
Inherited immune deficiencies rarely occur and are usually referred to as primary immunodeficiencies. These deficiencies may affect all immunoglobulins production, one class, or one or more subclasses. Some of the disorders include common variable immunodeficiency (CVID), x-linked agammaglobulinemia, severe combined immunodeficiency (SCID), hyper-IgM syndrome, Wiskott-Aldrich syndrome, ataxia telangiectasia, and agammaglobulinemia.
Immunoglobulins are usually present in the cerebrospinal fluid (CSF) in low concentrations. Immunoglobulin concentration may be higher in some cases, like with inflammatory conditions, multiple sclerosis and central nervous system infections (meningitis encephalitis).
A decrease in saliva IgA may occur with recurrent respiratory infections.
Most blood tests take only a few minutes. In cases where the vein is difficult to find, the healthcare provider may need to try more than once during the blood sample collection.
The immunoglobulin test is safe with minimal risks. Some people may feel faint or lightheaded after the test. If you have a phobia for needles or are anxious, inform your provider before the test and discuss ways to make the test easier.
You may experience mild soreness or a small bruise around the blood test site, lasting a few days. Ensure you seek medical care if the discomfort worsens or takes longer. Also, speak to your doctor if you have questions about the immunoglobulin test.
There are no specific symptoms of low immunoglobulin levels. Possible symptoms include multiple infections, opportunistic infections or recurrent infections, with or without chronic diarrhoea. A follow-up may be necessary if you have a family history of immunodeficiency. A careful medical history and thorough physical examination are essential for a diagnosis.
The normal range for adults includes:
You can book an appointment at Blood London for your immunoglobulin blood test. Contact us at 020 71830244 or [email protected] for more information on immunoglobulin blood tests or to schedule an appointment for your test.
Select the test that you would like to undergo
Go to the Harley Street clinic for your blood draw and pay for your test in person
As soon as the results are ready, the will be sent to you by your chosen method