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.