There are tests that can tell you if your system is producing the correct types of immune cells and if you have enough of them.
There are tests that can tell you if your system is producing the correct types of immune cells and if you have enough of them.

Everyone has an immune system that helps them fight off illnesses and infections. The system consists of different cell types that your body deploys to fight off microorganisms that can make you sick. The immune system works automatically and is usually very effective. 

You may wonder how well your immune system is working. There are tests that can tell you if your system is producing the correct types of immune cells and if you have enough of them. Not everyone needs their immune system tested, though. The testing is most helpful for diagnosing problems when the immune system is underperforming.

Who should get their immune system tested?

If your immune system is functioning normally, there is no need to have it tested. People with healthy immune systems may get common illnesses, but they can recover from them in a reasonable time frame. You may need some medicine when you get sick, such as requiring a prescription for antibiotics to recover from strep throat, but you will get better with appropriate treatment.

If your immune system isn’t working as well as it should, though, you will find that you have frequent illnesses that take a long time to recover from. They may not respond to typical treatments, so you won’t recover even after treatment. Mild illnesses such as common colds may develop into something more serious like bronchitis.

Some symptoms of an immune system deficiency include:

Immune system tests

If you have the signs of a possible immunodeficiency disorder, your doctor may order tests to understand what is causing your immune system to malfunction. 

Blood tests

Your doctor may order a complete blood count (CBC). Your doctor will take a sample of your blood and send it to a lab where it will be checked for signs of an immune disorder. They will check white blood cell counts and may examine these cells under a microscope to look for abnormalities. Your doctor may also have your blood checked for immunoglobulin levels and the levels of specific antibodies.

Skin tests

If your doctor suspects that you have a problem with immune cells known as T-cells, they will order a skin test. The doctor will inject a small amount of protein from an infectious organism under your skin. If you have a typical immune reaction with swelling, redness, or tenderness, your doctor will know your T-cells are working correctly. If the reaction doesn’t occur within 48 hours, you may have a T-cell disorder. You will need additional testing to identify the specific problem.


Your doctor may need to look at a sample of bone marrow or tissue from your lymph nodes. This will allow them to see if certain immune cells are present or not.

Genetic testing 

Some immune disorders are caused by genetic factors. Your doctor can analyze your genome to identify any genetic changes that could be causing immune system problems.

Tests for immunity to specific diseases

It's possible for doctors to check your blood for antibodies for specific illnesses, indicating immunity levels. They may do this during testing for immune system disorders to see if you have appropriate levels of antibodies from vaccines you received in the past. They can also check if you have antibodies from diseases you may have had, such as covid-19.


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Types of immune system disorders

There are two major categories of immunodeficiency disorder. 

Primary immunodeficiency

Primary immunodeficiency disorders are caused because the cells of your immune system are not working properly. You may have a problem with one or more types of immune system cells, including: 

  • B cells, white blood cells that produce antibodies (immunoglobulins)
  • T cells, white blood cells that help identify and destroy foreign or abnormal cells
  • Phagocytes, immune cells that destroy microorganisms
  • Complement proteins, protein cells that help immune cells fight illness and infection

There are more than 400 primary immunodeficiency disorders. These conditions are something you were born with, though symptoms might not develop until you're older. The causes are usually genetic, and the conditions tend to run in families. Your doctor will conduct specific tests to provide an exact diagnosis.

Secondary immunodeficiency

Secondary immune disorders occur as the result of another health condition. Your immune system may suffer due to specific conditions, including:

  • Illnesses such as diabetes or cancer
  • Certain medications or illicit drugs
  • Significant malnutrition
  • Age-related loss of immune function
  • HIV 

Treatment for immune system disorders

Once your doctor has determined what is causing your immune system issues, you will be able to decide on a treatment plan. Your doctor will probably caution you to reduce your risk of getting common illnesses by washing your hands, avoiding people you know are sick, and maintaining healthy lifestyle habits. 

Your doctor may prescribe antibiotics or antiviral drugs at the first sign of an illness. These medications can help you recover from minor illnesses without complications. Your doctor may also suggest getting certain vaccines to boost your immunity to vaccine-preventable illnesses like influenza, pneumonia, and shingles.

You may also need treatment for your underlying immune disorder, such as immunoglobulin therapy, stem cell transplant, or gene therapy. If you have another condition that affects your immune system, you will need to get treatment for that condition as well. Your doctor will help you decide how best to manage your overall health.


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Medically Reviewed on 11/29/2021

Centers for Disease Control and Prevention: “Primary Immunodeficiency (PI).”

Immune Deficiency Foundation: “About Primary Immunodeficiencies.”

Merck Manual: “Overview of Immunodeficiency Disorders.”