HIV/AIDS can be fairly unpredictable. You may feel well but it is hard to tell from that just what the virus is up to. Having regular health check ups can give you an early warning about changes in your health, and give you more time to decide what to do about them. It’s also important to monitor how you are responding to treatments so that you can respond quickly if, for example, you develop resistance to your drugs.
Most people with HIV/AIDS are monitored by general practitioners (GPs) with some experience in treating people with HIV.
You need to keep an eye on your viral load, CD4 counts, pap smear (women), sexually transmissible infections (PDF), your liver (if you also have hepatitis), your general health and your dental health.
In this section:
Viral Load
CD4 counts;
Putting it all together: Using viral load results and CD4 count results to inform treatments decisions
Common tests for monitoring side effects
Other tests that may help inform treatments decisions
Working with your general practitioner (PDF)
It might be useful for you to keep a health diary or notebook in which you record test results, treatments, symptoms, reactions to medications and other things associated with your HIV monitoring. This can be a valuable tool for tracking changes in your health.
Information in this section comes from HIV Tests and Treatments, AFAO, 4th edition, 2009, and AFAO Factsheets 2009
Last updated 6 January 2010
See also Fact Sheets:
Viral load (PDF)
Undetectable viral load and risk of HIV transmission: the ‘Swiss Statement’ (PDF)
Common Blood Tests (PDF)
Sexual health checks (PDF)
The importance of giving up smoking for people with HIV (PDF)
Viral load
‘Viral load’ is the term used to describe the amount of the HIV virus present in your bloodstream. Knowing how much HIV is present is an important indicator of how much your immune system is at risk of damage, how well your treatments are working, or whether you should consider starting or changing treatments. A viral load test is a simple blood test. The result of a test is given as the number of viral copies of HIV per millilitre of blood. A ‘copy’ is what HIV produces every time it grows inside a cell: the more copies, the more virus.
The amount of virus in your blood may range from a very small number of copies in your blood (below 50 copies per millilitre of blood) to levels in the thousands, hundreds of thousands, or even millions. In some Australian states and territories the tests can measure down to 40 copies per millilitre of blood.
Understanding Your Viral Load results
Viral load is perhaps the simplest and easiest HIV test to understand as it is simply a count of the virus expressed in number per millilitre. When you first have your viral load tested, you will usually have two tests several weeks apart, which gives a result known as your ‘baseline’, and which can be used to compare changes over time. These results can be a useful guide if you are considering treatment:
a) ‘Undetectable’ viral load?
One result you can get back from a viral load test result is ‘undetectable’. Undetectable viral load does not mean that you have ‘cleared’ the virus from your body. It means that HIV is present, but in very small amounts (below the capacity of current commercial tests to accurately measure: that is, below 40 to 50 copies per millilitre of blood). Virus at such levels is replicating so slowly that little, if any, damage will be happening to your CD4 cells and immune system.
Viral load tests are slowly becoming more sensitive. However, special laboratory tests are able to detect HIV in even minute quantities. HIV infects cells which may remain active in lymph glands, known as resting cells, and has also been shown to infect small amounts of other types of cells. To totally cure or eradicate HIV, you would need to also eradicate the virus in these ‘resting cells’.
b) Detectable viral load results
You will often be told that your viral load result is ‘high’ (i.e. more than 100,000 copies per ml), ‘moderate’ (i.e. 10,000 to 100,000 copies per ml), or ‘low’ (i.e. less than 10,000 copies per ml). On their own your viral load results are no cause for alarm. For example, a high viral load result does not mean you are going to be sick tomorrow. Or a low result after your results have been undetectable for some time does not mean you have suddenly “failed” in any way.
Your viral load level is a rough guide to the likelihood of future damage to the immune system. So if your viral load is high it means that future damage is more likely. If it is low or undetectable it means future damage is less likely.
In order to make decisions about treatments, the viral load has to be read in conjunction with the CD4 cell count.
Viral load and the pattern over time is important
You may be asked to have viral load tests fairly frequently so you and your doctor can keep track of changes over time, or of any sudden variations between test results. In fact, an unexplained and significant upward trend in viral load over a number of tests may be a stronger indicator that you should consider changing or starting treatments than a single, detectable result in isolation. The magnitude of the change is important. For example, a rise of viral load from 5,000 to 6,000 does not necessarily indicate there is a problem. But a rise from 5,000 to 50,000 may suggest that the virus is beginning to replicate very rapidly for some reason, and that you should take this into consideration when thinking about starting or changing treatments
Other factors can affect viral load
No one viral load result should be considered alone. It’s the pattern over time which counts. There are a number of reasons why you may experience a sudden temporary rise, or ‘spike’ in your viral load.
These include:
another infection (e.g. the flu, hepatitis, or another sexually transmitted infection such as gonorrhoea or syphilis); and recent vaccination (eg. routine travel-related vaccinations or hepatitis A or B vaccination), which can stimulate your immune system for a brief period causing only a temporary rise.
Viral load and “infectiousness”
Viral load tests tell you how much virus is in your blood. But HIV is also present in other body fluids, including semen, vaginal fluids and CSF (cerebrospinal fluid)—the fluid which protects your brain. The level of virus in your blood is often different to the amounts in other body fluids. This difference can be caused by a number of factors. For this reason, blood viral load tests should not be used to judge the likelihood of HIV transmission. It is possible to have low or undetectable blood viral load, but higher levels in semen or vaginal fluids.
 While research suggests an undetectable viral load reduces the risk of HIV transmission, an undetectable viral load has not yet been proven to completely eliminate the risk of transmitting the virus. The use of viral load in prevention is not a substitute for safe sex.
Viral load over time without treatment
The typical picture of viral load over time is given at left. Soon after initial infection there is a peak in viral load until the immune system responds. Then, for a period of years the immune system and the virus are engaged in a balancing act, though in nearly all cases the immune system is still being weakened. Throughout this period, the virus is still active. Eventually, the virus may overwhelm the immune system.
If you are not taking antiviral treatments, you will probably be advised to have a viral load test each time you have a CD4 or T-cell count. Comparing these results with your baseline viral load will alert you and your doctor to any changes in your immune system or your health.
Ask your doctor to explain the meaning of any changes in your viral load. It is quite common for viral load to change a bit with each test. What is important is the magnitude of the change. Doctors use a mathematical scale called a logarithmic (“log”) scale to measure the significance of any changes. It is only changes of a significant magnitude that are considered important.
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The CD4 count
The other test that is critical in managing HIV and understanding how it is affecting you and your body, is the CD4 or T-cell count. CD4 cells are a critical part of your immune system. They are infected and destroyed by HIV. Sometimes, they can be depleted to such dangerous levels that they are unable to play their part in helping your immune system work properly. If this happens, you could be at risk of developing AIDS or AIDS related illnesses.
CD4 counts used to be the only way to understand how HIV was affecting your immune system. The CD4 count is a measure of the damage already done. The viral load is a measure of the risk of future damage. A general guide to CD4 test results is:
500 to 1,350 CD4 is the ‘normal’ range for adults; more than 500 CD4 indicates little or no immune system damage; between 500 and 250 CD4 cells indicates some damage but it is unlikely you will be at risk of major opportunistic infections; and less than 250 CD4 indicates more serious immune system damage and suggests that you could be at risk of serious opportunistic illnesses.
CD4 percentages measure the proportion of CD4 cells against other types of white blood cells. The percentage is more an indication of the stability of CD4 count over time, rather than the actual CD4 count. The percentage can indicate how stable the CD4 count is and may vary less than an actual CD4 count. For example, a person with a CD4 count of 350 at 23% could indicate more stability and less chance of disease progression than a person with a CD4 count of 500 at 15%. Together with viral load and the CD4 count, it’s another result that is used by your doctor to assist in determining your optimal treatment strategies.
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Putting it all together
Using viral load results and CD4 count results to inform treatments decisions
To get the best picture, viral load test, CD4 counts and CD4 percentage results should be considered together. These results can be used to determine:
the level of activity of the virus in your bloodstream; the level of damage to your immune system; when to start antiviral treatment; if the current antiviral treatments are working, and whether it may be necessary to change treatments; and when to take preventative medicines (prophylaxis) to decrease the chances of getting some of the more common opportunistic illnesses associated with AIDS.
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Common tests for monitoring side effects
Viral load and CD4 cell count results are two of the main tests used to inform treatment decisions about starting or changing treatments. Usually every time you have regular blood tests a whole range of other tests are done. Some of these are useful in monitoring for possible drug side effects and potential organ damage. The results of these tests may also influence decisions to commence or change your HIV treatments.
Some of the common tests include:
Glucose, triglyceride and cholesterol levels:The two major fats (lipids) in the blood are triglycerides and cholesterol. Glucose, triglyceride, and cholesterol levels are most reliably measured in the fasted state, that is, in the morning before eating. Certain anti-HIV therapies can increase cholesterol, triglyceride, and glucose levels in some people, which may increase the risk of heart attack and stroke, and can be associated with lipodystrophy (the redistribution of body fat).
Liver function tests:There are a range of tests which taken together give an indication of the health of the liver. The liver can be damaged by hepatitis, alcohol and other drugs, being overweight, and by HIV antiviral drugs directly – so it is important to keep a watch on liver function.
Kidney function: Kidney function is normally measured by the blood levels of ‘waste’ products such as urea and creatinine. Some HIV antiviral drugs can affect the levels of these waste products because they compete with them for excretion in the kidney. Some HIV antiviral drugs may have an impact on kidney function.
Platelet count: Platelets are important in helping your blood clot in response to a cut or wound. Some HIV antiviral drugs – particularly nucleoside analogues (e.g. AZT, d4T) – can decrease the platelet count.
Haemoglobin and Haematocrit: Haemoglobin measures the levels of the key protein which transports oxygen around the body. Haematocrit is a measure of the proportion of blood that is red blood cells. Low haemoglobin levels or a low haemotocrit can be an indicator of anaemia – a known side effect of some HIV antiviral drugs.
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Other tests that may help inform treatments decisions
Resistance testing
The most common test to measure possible drug resistance is known as ‘Genotyping’. The purpose of this test is to detect the presence of known virus mutations associated with drug resistance. (See Resistance Page 16) This test is called a ‘genotypic resistance assay’ or ‘GRA’. It is used to compare the genetic code of the sample of HIV virus being tested against a ‘wildtype’ (the most common form of HIV virus). This test can only be performed if you have a viral load over about 2000 copies per millilitre of blood.
Knowing which treatments you are potentially resistant to and which treatments are effective against your virus is useful in determining your optimal treatment strategy. The current treatment guidelines suggest that this test should be performed:
prior to commencing treatments; to assist in correctly selecting treatments when considering changing treatments; if there is indication of viral load change during treatment; and, less often, within 4 weeks after discontinuing or stopping treatments.
Another test used to measure resistance is known as ‘phenotyping’. This test is called a ‘phenotypic assay’. It measures the virus’s ability to grow in the presence of different combinations of antiretroviral treatments. This test provides a direct and quantitative measure of the likelihood of resistance developing for individual treatments and can also be used to determine the optimal dosing of treatments.
The third approach to resistance testing is the ‘virtual phenotype’. This test is really a genotype test that is interpreted with the aid of a large database of samples of known genotype and phenotype data. One drawback of this particular form of resistance testing is that the results are dependant on the number of known matches, but its main strength is that for people not on new drugs, as it is a simpler method of determining the likelihood of developing resistance.
Phenotyping is still relatively expensive compared to genotyping and virtual phenotyping, and is currently not available in Australia. As all of these tests are currently not covered under Medicare, the availability and cost of these tests varies. Your doctor or treatments officer will be able to provide more information as to the cost and availability in your area and what these tests may mean for you.
Abacavir Hypersensitivity
This test is rapidly becoming widespread and is a genetic test used to determine the likelihood of a possibly fatal side effect of Abacavir (an HIV antiviral drug) known as Abacavir hypersensitivity reaction. Wherever possible, it should be performed by your doctor prior to commencing Abacavir.
Therapeutic drug monitoring (TDM)
Therapeutic drug monitoring (TDM) is used to help individualize anti-HIV therapy by measuring the amount of drug in an individual’s blood (plasma) or cerebral (spinal) fluid. This is important because different people absorb, process, and eliminate drugs at different rates, and blood and cerebral fluid levels may vary considerably among individuals taking the same doses of the same medications. Ideally, the lowest plasma drug concentration between doses (the trough level, or Cmin) should still be high enough to inhibit HIV, but the highest concentration (the peak level, or Cmax) should not cause intolerable side effects.
Some, but not all, studies have shown that using TDM to guide treatment decisions increases the chance of successful viral suppression and can assist in minimising side effects; however, drug level monitoring is not appropriate for all anti-HIV drugs.
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