Post by Admin on Mar 23, 2016 19:14:26 GMT -8
WHAT IS A CD4 COUNT AND WHY IS IT IMPORTANT?
A CD4 count is a lab test that measures the number of CD4 T lymphocytes (CD4 cells) in a sample of your blood. In people with HIV, it is the most important laboratory indicator of how well your immune system is working and the strongest predictor of HIV progression.
A T cell is a type of white blood cell. White blood cells are also called lymphocytes. These cells fight off diseases. The two categories of lymphocytes are T cells and B cells. The T cells respond to viral infections, while the B cells fight bacterial infections. Your body sometimes has too many or too few T cells. This may be a sign that your immune system isn’t functioning properly.
To understand why it’s imp ortant, it’s helpful to know what CD4 cells are. CD4 cells (often called T-cells or T-helper cells) are a type of white blood cells that play a major role in protecting your body from infection. They send signals to activate your body’s immune response when they detect “intruders,” like viruses or bacteria.
A T cell count may also be known as a thymus-derived lymphocyte count, or a T lymphocyte count.
Why Do I Need a T Cell Count?
Your doctor may order a T cell count if you’re having symptoms of an immunodeficiency disorder, such as HIV, or other conditions, such as cancer or leukemia.
The symptoms of an immunodeficiency disorder include:
A low T cell count is more common than a high T cell count. Low T cell counts usually indicate problems with your immune system or lymph nodes. Low T cell counts may be due to:
Less often, you might have a T cell count that’s higher than normal. A high T cell count can be due to:
How Do I Prepare for a T Cell Count?
A T cell count requires only a small sample of your blood. There’s little you need to do to prepare for it.
Be sure to tell your doctor about all the medications you’re taking, including any over-the-counter and prescription medications or herbal supplements, before your test. Certain medications can impact your T cell count, which will alter the results of your test. Your doctor may ask you to stop taking your medications for a little while, or they may change the dosage before your test.
Medications that may affect your T cell count include:
***Recent surgery or highly stressful experiences can also affect your T cell count. You should tell your doctor if any of these situations apply to you.
How Is a T Cell Count Determined?
Remember, your doctor only needs a small sample of your blood to get a T cell count. This procedure is also known as a blood draw or venipuncture. You may have the test in a medical laboratory or a doctor’s office.
***You’ll be free to go about your day following the blood draw. Your sample will go to a laboratory, where technicians will count the number and type of white blood cells present.
What Are the Risks Associated with a T Cell Count?
There are very few risks associated with a T cell count. However, people with compromised immune systems often have this test. They may be at greater risk for developing an infection than the rest of the population.
Other possible risks of a T cell test include:
Once a person is infected with HIV, the virus begins to attack and destroy the CD4 cells of the person’s immune system. HIV uses the machinery of the CD4 cells to multiply (make copies of itself) and spread throughout the body. This process is called the HIV life cycle.
So, during your regular check-ups, your HIV care provider will want to know your CD4 count to help keep track of how healthy you are and whether the virus has progressed in your body:
Your CD4 count is also used to help you and your HIV care provider decide when to start antiretroviral therapy (ART).
ART involves taking a combination of HIV medicines (called an HIV regimen) every day. It prevents HIV from multiplying and destroying your infection-fighting CD4 cells. ART can’t cure HIV, but it can help you live a longer, healthier life and reduce your risk of HIV transmission.
ART is recommended for everyone with HIV, but the urgency to start ART is greater in people with low or rapidly falling CD4 counts. A falling CD4 count indicates that HIV is advancing and damaging your immune system.
After you start ART, your HIV care provider will use your CD4 count as one way to check how well your medication is working to monitor the effectiveness of your HIV regimen. Your HIV care provider will also monitor your CD4 count to determine whether it has fallen to a level at which you might be at risk for certain opportunistic infections. In that case, your HIV care provider may prescribe some additional medications to prevent other infections.
WHEN AND HOW OFTEN DO I NEED A CD4 COUNT?
Your HIV care provider will order a CD4 count at your first visit after you are diagnosed in order to establish a baseline level.
After that, current HIV treatment guidelines recommend that your HIV care provider order a CD4 test every 3 to 6 months when you are starting ART to see how well you are responding to treatment. Depending on your health status, your HIV care provider may switch to every 6 to 12 months once treatment has increased your CD4 levels to higher levels and your viral load is suppressed. If your CD4 count reaches normal levels and your viral load remains suppressed, your HIV care provider may not check your CD4 count unless there is a change in your health or viral load.
Your CD4 count can vary from day to day. It can also vary depending on the time of day your blood is drawn and on whether you have other infections or illnesses, like the flu or sexually transmitted infections (STIs). The trend of your CD4 count (whether it’s rising or falling) over time is what’s really important—not an individual test result.
CD4 COUNT: A SUMMARY
A CD4 count is a lab test that measures the number of CD4 T lymphocytes (CD4 cells) in a sample of your blood. In people with HIV, it is the most important laboratory indicator of how well your immune system is working and the strongest predictor of HIV progression.
A T cell is a type of white blood cell. White blood cells are also called lymphocytes. These cells fight off diseases. The two categories of lymphocytes are T cells and B cells. The T cells respond to viral infections, while the B cells fight bacterial infections. Your body sometimes has too many or too few T cells. This may be a sign that your immune system isn’t functioning properly.
To understand why it’s imp ortant, it’s helpful to know what CD4 cells are. CD4 cells (often called T-cells or T-helper cells) are a type of white blood cells that play a major role in protecting your body from infection. They send signals to activate your body’s immune response when they detect “intruders,” like viruses or bacteria.
A T cell count may also be known as a thymus-derived lymphocyte count, or a T lymphocyte count.
Why Do I Need a T Cell Count?
Your doctor may order a T cell count if you’re having symptoms of an immunodeficiency disorder, such as HIV, or other conditions, such as cancer or leukemia.
The symptoms of an immunodeficiency disorder include:
- frequently recurring infections
- severe infections from bacteria or other organisms that don’t usually cause severe infections
- trouble recovering from illnesses
- infections that don’t respond to treatments
- recurring fungal infections, such as yeast infections
- recurring parasitic infections
- viral infections, such as influenza
- aging
- immunodeficiency disorders
- exposure to radiation
- HIV and AIDS
- cancers that affect the blood or lymph nodes, such as Waldenstrom’s macroglobulinemia, leukemia, and Hodgkin’s disease
- congenital T cell deficiency in rare cases
Less often, you might have a T cell count that’s higher than normal. A high T cell count can be due to:
- infectious mononucleosis, which is also known as mono or the kissing disease
- acute lymphocytic leukemia, which is a type of cancer that affects the white blood cells
- multiple myeloma, which is a type of cancer that affects the plasma in bone marrow
How Do I Prepare for a T Cell Count?
A T cell count requires only a small sample of your blood. There’s little you need to do to prepare for it.
Be sure to tell your doctor about all the medications you’re taking, including any over-the-counter and prescription medications or herbal supplements, before your test. Certain medications can impact your T cell count, which will alter the results of your test. Your doctor may ask you to stop taking your medications for a little while, or they may change the dosage before your test.
Medications that may affect your T cell count include:
- chemotherapy drugs
- radiation therapy
- corticosteroids
- immunosuppressive drugs or anti-rejection drugs
***Recent surgery or highly stressful experiences can also affect your T cell count. You should tell your doctor if any of these situations apply to you.
How Is a T Cell Count Determined?
Remember, your doctor only needs a small sample of your blood to get a T cell count. This procedure is also known as a blood draw or venipuncture. You may have the test in a medical laboratory or a doctor’s office.
- A healthcare provider will begin by cleaning an area of skin on your arm or hand with antiseptic to help prevent infection.
- They’ll tie an elastic band around your upper arm so that blood collects in your vein.
- Next, they’ll insert a sterile needle into your vein and draw blood into a tube. The amount of blood drawn depends on the number of tests that your doctor ordered. It should take no longer than a couple of minutes to collect the blood sample needed.
- You may feel some pain while having your blood drawn. This usually feels like a pricking or stinging sensation. You can help ease this pain by relaxing your arm. When the technician finishes drawing blood, they’ll remove the elastic band and the needle and apply a bandage to the puncture wound. You should apply pressure to the wound to stop bleeding and prevent bruising.
***You’ll be free to go about your day following the blood draw. Your sample will go to a laboratory, where technicians will count the number and type of white blood cells present.
What Are the Risks Associated with a T Cell Count?
There are very few risks associated with a T cell count. However, people with compromised immune systems often have this test. They may be at greater risk for developing an infection than the rest of the population.
Other possible risks of a T cell test include:
- multiple puncture wounds if the technician has trouble finding a vein
- excessive bleeding
- lightheadedness or fainting
- hematoma, which is a collection of blood under the skin
- an infection at the puncture site
So, during your regular check-ups, your HIV care provider will want to know your CD4 count to help keep track of how healthy you are and whether the virus has progressed in your body:
- The CD4 count of an uninfected adult/adolescent who is generally in good health ranges from 500 cells/mm3 to 1,200 cells/mm3.
- A very low CD4 count (less than 200 cells/mm3) is one of the ways to determine whether a person living with HIV has progressed to stage 3 infection (AIDS).
Your CD4 count is also used to help you and your HIV care provider decide when to start antiretroviral therapy (ART).
ART involves taking a combination of HIV medicines (called an HIV regimen) every day. It prevents HIV from multiplying and destroying your infection-fighting CD4 cells. ART can’t cure HIV, but it can help you live a longer, healthier life and reduce your risk of HIV transmission.
ART is recommended for everyone with HIV, but the urgency to start ART is greater in people with low or rapidly falling CD4 counts. A falling CD4 count indicates that HIV is advancing and damaging your immune system.
After you start ART, your HIV care provider will use your CD4 count as one way to check how well your medication is working to monitor the effectiveness of your HIV regimen. Your HIV care provider will also monitor your CD4 count to determine whether it has fallen to a level at which you might be at risk for certain opportunistic infections. In that case, your HIV care provider may prescribe some additional medications to prevent other infections.
WHEN AND HOW OFTEN DO I NEED A CD4 COUNT?
Your HIV care provider will order a CD4 count at your first visit after you are diagnosed in order to establish a baseline level.
After that, current HIV treatment guidelines recommend that your HIV care provider order a CD4 test every 3 to 6 months when you are starting ART to see how well you are responding to treatment. Depending on your health status, your HIV care provider may switch to every 6 to 12 months once treatment has increased your CD4 levels to higher levels and your viral load is suppressed. If your CD4 count reaches normal levels and your viral load remains suppressed, your HIV care provider may not check your CD4 count unless there is a change in your health or viral load.
Your CD4 count can vary from day to day. It can also vary depending on the time of day your blood is drawn and on whether you have other infections or illnesses, like the flu or sexually transmitted infections (STIs). The trend of your CD4 count (whether it’s rising or falling) over time is what’s really important—not an individual test result.
CD4 COUNT: A SUMMARY
- A CD4 count ranges from 500–1,200 cells/mm3 in healthy adults/adolescents.
A CD4 count of fewer than 200 cells/mm3 is one of the qualifications for a diagnosis of stage 3 infection (AIDS).- ART is recommended for everyone with HIV, but the urgency to start ART is greater in people with low or rapidly falling CD4 counts.
- Your CD4 count can vary from day to day. It can also vary depending on the time of day your blood is drawn and on whether you have other infections or illnesses, like the flu or STIs.
- Typically, your HIV care provider will check your CD4 count every 3 to 6 months when you are starting ART. Once your CD4 level rebounds and your viral load is suppressed, your provider may check your CD4 count less frequently.