What other tests do I need?

2 August 2017. Related: HIV positive people, Resources.

After you test HIV positive, your doctor will need to run other tests.

HIV test for recent infection (RITA, STARHS)

In the UK, another type of HIV test can help know whether this is a recent infection – ie within the last six months. This is called RITA (Recent Infection Treatment Algorithm) or STARHS, or an avidity test. The results are interpreted together with your recent risk of exposure and/or whether you had symptoms of early infection.

CD4 and viral load: two essential blood tests

The two test results that tell you most about HIV and your general health are your CD4 count and your viral load.

These two blood tests can tell you nearly everything you need to know about how HIV has progressed.

With both tests, the pattern from several results is more important than any single result. The first results are still important as a guide in case they show a problem.
The results over time are more important though to see whether they are getting higher or lower over time, and how quickly or slowly any changes occur.
The trend is often more important than any single result. So a low CD4 count is not necessarily a reason to start treatment if it is still steadily rising. On the other hand, a high CD4 count might be a reason to start treatment if it is dropping relatively quickly.

CD4 count

The CD4 count tells you how much or little damage HIV has caused to your immune system. Results are given as the number of cells in a cubic millimetre of blood (cells/mm3).

Without HIV treatment (ART), the CD4 count is likely to fall over time.
In the UK, HIV treatment is currently recommended at any CD4 count.

Viral load

The viral load test tells you how much HIV is circulating in your body. The result is given as the number of copies of HIV in a millilitre of blood (copies/mL).

Viral load is highest in the 2 – 4 weeks after infection. During this time, called seroconversion, viral load can be over 10 million copies/mL.
The general pattern is that over the next few months, without ART your immune system will control HIV and brings viral load down. This is usually to less than 50,000 and often much lower.
Then, without ART, viral load gradually increases, with most people starting treatment when viral load is between 50,000 – 100,000 copies/mL.
ART reduces viral load to undetectable levels. This leads to better health and prevent HIV transmission.

Resistance tests

In the UK, approximately 10% of people diagnosed with HIV with have been infected with a virus that is already resistant to one of more HIV drugs. This information is important even if you are not expecting to start treatment for a while.

Some drug resistance becomes more difficult to detect as you get further from the time of infection. This is why UK guidelines recommend a routine drug resistance test when you are first diagnosed. You may need to ask your clinic for this test and for the results.

Other tests

Your doctor should give you a full medical check-up.

This should include:

Your height, weight, waist circumference, blood pressure and full medical history.
Blood tests to check for other infections, including sexually transmitted infections and hepatitis A, B and C, and TB if you are at risk.
Other bloods tests with check your liver and kidney function, blood lipids (cholesterol etc).
The subtype of HIV that you have.
You should also have the chance to speak to a health advisor and/or counsellor over your psychological health and your reaction to the HIV diagnosis.

All these tests are to get a good overview of your current health in case referrals or treatment is needed, and to get baseline results to see how your health changes over time.