Is a B and T Cell Screen?
The B and T cell screen is a blood test that measures the level
of lymphocytes in your blood. Lymphocytes are
a type of white blood cell (WBC) that helps your body’s immune system identify
and fight off organisms or substances that cause diseases.
The two predominant types of lymphocytes that are created in your
bone marrow are B cells and T cells. An antigen is a foreign substance, such as
a chemical, virus, or bacteria. When an antigen enters your body, B cells
produce antibodies that
attach to the substance. However, these antibodies aren’t strong enough to kill
the antigen. T cells direct your body’s response to the presence of a foreign
molecule and kill infected cells.
There are two parts to your body’s immune system. The first is
innate protection, which consists of proteins and cells that are always in your
body. This innate protection provides a general defense that’s always ready to
protect your body from foreign invaders.
The second part of your immune system is adaptive protection,
which is made up of the B and T cells. The B and T cells are produced to target
invaders that make it past your innate immune defenses. When antigens bypass
the first system of protection, your body’s best defense is its B and T cells.
When your immune system is weakened or damaged, your B and T cells are unable
to function correctly.
Sometimes, the immune system attacks and destroys healthy tissue
because it can’t tell the difference between antigens and healthy cells. When
this happens, it’s known as an autoimmune
Is the Purpose of a B and T Cell Screen?
The B and T cell screen may be performed if you have symptoms of
diseases that weaken your immune system or diseases of your blood and bone
marrow. Some common symptoms and conditions include:
- a low WBC count
- thyroid problems
- liver failure
- swollen lymph nodes
- recurrent or unusual infections
Should My Doctor Know Before I Take the Test?
Before any medical test is performed, tell your doctor about any
of the following that you’re taking:
- prescription medications
- non-prescription medications
- dietary supplements
Make sure to tell your doctor if you have an autoimmune disease, have
recently had surgery, or if you’re currently taking medications to suppress
your immune system. These factors may affect your results.
Happens During the Test?
The B and T cell screen is a blood test. The following steps are
- A healthcare provider will tie an elastic band
called a tourniquet above the site where the blood will be taken, which is
usually on the inside of your elbow.
- They’ll clean the area and sterilize it with
antiseptic before inserting a small needle directly into your vein. Most people
feel a sharp pain at the initial needle poke that quickly fades as their blood
- Within a few minutes, the healthcare provider
will remove the needle and apply pressure to the site with a cotton ball.
- They’ll place a bandage on the site, and you’ll be
free to leave.
Blood tests are typically painless and carry low risk. However,
you may experience slight bruising or temporary discomfort after your blood is
drawn. Some people experience minor dizziness after having blood drawn. Let
your healthcare provider know if you feel dizzy, faint, or nauseous.
Does an Abnormal Result Mean?
Your immune system is a very complex part of your body, and
abnormal cell counts can indicate a variety of disorders.
Common diseases and disorders associated with increased levels of T or B
- certain types of leukemia
- tuberculosis (TB)
- infectious mononucleosis, or mono, which is a
viral infection that affects the lymph glands
- multiple myeloma, which is a cancer that
originates in the plasma and bone marrow
- DiGeorge syndrome, which is a chromosomal
disorder that’s associated with heart defects and thyroid issues
of T or B cells are often associated with:
- congenital, or inherited, immunodeficiency
- certain cancers in your blood
- certain cancers in your lymphatic cells
- acquired immune disorders, such as HIV or AIDS
Additional tests may be necessary to rule out certain disorders
and make a diagnosis. These may include:
- an IgE level measurement to determine the amount
of a certain type of antibody in your blood
- a lymph node biopsy
- a peripheral blood smear
- a bone marrow biopsy
Your doctor will evaluate your results and discuss the best form
of treatment with you.