UNDERSTANDING LAB TESTS - HIV VIRAL LOAD TESTS
An important part of your HIV health care involves lab work at regular intervals to monitor the progression of your HIV disease and to provide information that will help your specialist make decisions regarding your treatment plan. Knowing and understanding the results of lab tests is an important way for you to understand and learn to live with HIV.
The HIV viral load test measures the amount of HIV in your blood and shows how actively the virus is reproducing in the body. The viral load is counted and reported in the form of copies per milliliter (ml) of blood. There are two different types of HIV viral load tests: polymerase chain reaction (PCR) test and the branched DNA (b-DNA) test. It is not necessary to understand how the tests differ, but you should know that the different test methods will give different results for the same sample and the tests are not interchangeable. Both tests measure the amount of HIV in the blood, but the results of the two tests do not correlate and it is like trying to compare apples to oranges. Because of this, you should have the same test done by the same lab each time; your provider will always order the same test.
When used in combination with the CD4 cell count (T cell) test, the HIV viral load test is used to monitor the status of HIV disease and to predict the future course of HIV. It is essential in determining when to start treatment for HIV with antiretroviral medications. It is also useful in monitoring the effectiveness of the medications. This test is done when you are first diagnosed with HIV as a baseline and then every 3 months, but it may be done more frequently if you are beginning medications, are changing medications, or have been missing doses of medications. To monitor stable long term therapy, the viral load and CD4 counts are done every 3-6 months, with most HIV treatment specialists preferring to do them at 3 month intervals.
A high viral load measurement (10,000 copies to over 1 million copies) indicates that the HIV is reproducing rapidly and that the disease will most likely progress faster than if the viral load measurement is lower. Current U.S. Government guidelines recommend that treatment with antiretroviral (ARV) medications be considered when the viral load is at or greater than 50,000 copies, although treatment can be considered with lower levels, especially if symptoms of HIV disease are present. Once starting on ARV medications to suppress the activity of the HIV, the viral load level will fall steadily to the goal of undetectable, which is less than 50 copies. Undetectable viral load means that the level of virus in your blood is below the lowest level that the test can detect, but it does not mean that you are cured. The viral load test determines the amount of virus that can be detected in the blood. It is important to note that only about 5% of the HIV in the body of an infected person is detectable in the blood. This test does not measure the amount of HIV that is present in other body tissues like the lymph nodes, spleen or brain. If the viral load level is low or is below the level of detection because you are taking medications to treat HIV, you can still infect others with the virus. HIV is still present in your body and in body fluids. Although the risk of passing the virus to another person is lower with a lower viral load, there is no safe level and infecting others is always possible.
If the viral load level does not fall to the level of undetectable or if it increases after a period of being undetectable, this may indicate that the medications you are taking are no longer effective (your virus has become resistant to them) or that you are not taking the medications exactly as prescribed. It is important to take the medications exactly as you are instructed to do, including paying attention to the timing and any food or meal restrictions or other drug interactions. An undetectable viral load reduces the risk of disease progression by preserving the integrity of the CD4 cells and the body's immune function, keeping you healthier for a longer period of time.
Research has recently noticed that there is a common phenomenon referred to as viral load "blips", in which there is a slight rise in the viral load from an undetectable level to a low level (less than 500 copies) and a spontaneous return to an undetectable level. This does not seem to indicate that the HIV is becoming resistant to the medication, as long as the level returns to undetectable and stays at that level. If you have recently received an immunization (like a flu or pneumonia shot) or if your body is fighting off an infection (like a cold), the viral load may blip and then return to undetectable. The important thing is the trend in the results. If the viral load goes up and stays up, something is wrong with your treatment.
As a final note, I will repeat that a viral load that is undetectable does not mean that the HIV is cured and it does not mean that you can not infect others. You must still practice safe sex and use condoms with all intimate sexual activity to avoid passing the infection to your partner.
The HIV viral load test measures the amount of HIV in your blood and shows how actively the virus is reproducing in the body. The viral load is counted and reported in the form of copies per milliliter (ml) of blood. There are two different types of HIV viral load tests: polymerase chain reaction (PCR) test and the branched DNA (b-DNA) test. It is not necessary to understand how the tests differ, but you should know that the different test methods will give different results for the same sample and the tests are not interchangeable. Both tests measure the amount of HIV in the blood, but the results of the two tests do not correlate and it is like trying to compare apples to oranges. Because of this, you should have the same test done by the same lab each time; your provider will always order the same test.
When used in combination with the CD4 cell count (T cell) test, the HIV viral load test is used to monitor the status of HIV disease and to predict the future course of HIV. It is essential in determining when to start treatment for HIV with antiretroviral medications. It is also useful in monitoring the effectiveness of the medications. This test is done when you are first diagnosed with HIV as a baseline and then every 3 months, but it may be done more frequently if you are beginning medications, are changing medications, or have been missing doses of medications. To monitor stable long term therapy, the viral load and CD4 counts are done every 3-6 months, with most HIV treatment specialists preferring to do them at 3 month intervals.
A high viral load measurement (10,000 copies to over 1 million copies) indicates that the HIV is reproducing rapidly and that the disease will most likely progress faster than if the viral load measurement is lower. Current U.S. Government guidelines recommend that treatment with antiretroviral (ARV) medications be considered when the viral load is at or greater than 50,000 copies, although treatment can be considered with lower levels, especially if symptoms of HIV disease are present. Once starting on ARV medications to suppress the activity of the HIV, the viral load level will fall steadily to the goal of undetectable, which is less than 50 copies. Undetectable viral load means that the level of virus in your blood is below the lowest level that the test can detect, but it does not mean that you are cured. The viral load test determines the amount of virus that can be detected in the blood. It is important to note that only about 5% of the HIV in the body of an infected person is detectable in the blood. This test does not measure the amount of HIV that is present in other body tissues like the lymph nodes, spleen or brain. If the viral load level is low or is below the level of detection because you are taking medications to treat HIV, you can still infect others with the virus. HIV is still present in your body and in body fluids. Although the risk of passing the virus to another person is lower with a lower viral load, there is no safe level and infecting others is always possible.
If the viral load level does not fall to the level of undetectable or if it increases after a period of being undetectable, this may indicate that the medications you are taking are no longer effective (your virus has become resistant to them) or that you are not taking the medications exactly as prescribed. It is important to take the medications exactly as you are instructed to do, including paying attention to the timing and any food or meal restrictions or other drug interactions. An undetectable viral load reduces the risk of disease progression by preserving the integrity of the CD4 cells and the body's immune function, keeping you healthier for a longer period of time.
Research has recently noticed that there is a common phenomenon referred to as viral load "blips", in which there is a slight rise in the viral load from an undetectable level to a low level (less than 500 copies) and a spontaneous return to an undetectable level. This does not seem to indicate that the HIV is becoming resistant to the medication, as long as the level returns to undetectable and stays at that level. If you have recently received an immunization (like a flu or pneumonia shot) or if your body is fighting off an infection (like a cold), the viral load may blip and then return to undetectable. The important thing is the trend in the results. If the viral load goes up and stays up, something is wrong with your treatment.
As a final note, I will repeat that a viral load that is undetectable does not mean that the HIV is cured and it does not mean that you can not infect others. You must still practice safe sex and use condoms with all intimate sexual activity to avoid passing the infection to your partner.
Labels: hiv treatment, hiv viral load test
posted by Laurie @ 2/09/2007
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