Blood monitoring for people with HIV

Every time you visit your HIV clinic for a check-up you’ll have some blood tests. Which blood tests you have and how often you have them will depend on:

• whether you’re taking HIV treatment
• how long ago you started HIV treatment
• how well your treatment is working
• any recent changes to your medication.

It will also depend on your age, gender, and if you have any other health conditions.

What blood tests will I have at my HIV clinic appointment?

Some of the blood tests you have at your HIV clinic are directly related to HIV. There is more information about these tests on the following pages:

• viral load
• CD4 cell counts
• CD4/CD8 ratio.

You will also have blood tests at your clinic appointment that look at other health markers in your blood. This is because:

• HIV can cause changes in your body that you and your doctor should be aware of.
• HIV treatment can cause side effects, such as problems with your liver, kidneys, bones, or blood fats (lipids), which you won’t always be able to feel or see.
• If you do have certain health problems, or you are at high risk of them, you might need to adjust your HIV treatment. Your doctor will tell you if they think you need to do this.

How should I read my blood test results?

It’s usually best to look at the trends in your results over time, rather than focusing too much on one result. Your doctor will talk to you about the results of your blood tests to help decide the best healthcare plan for you. They might not always mention the results of tests if the results are normal, but you can always ask for more information.

We haven’t provided information on the normal ranges of blood test results here. This is because these can be different depending on all sorts of factors. This includes your age, your gender, and even the way your blood test was carried out.

What are the most common blood tests?

There are some blood tests that HIV clinics regularly use to check your health and see if your medication is causing any side effects. Some of these tests are called ‘routine blood tests’. This means that you’ll have them every time you have blood taken at your clinic or on a regular basis, such as once a year. Some others you’ll only have if they are needed. They have been grouped together below according to what they are for. 

Monitoring your general health

Some blood tests can be used to help doctors understand how healthy certain parts of your body are. A group of tests looking at one body part are sometimes called a ‘profile’. These tests will usually be done at least once a year.

• Renal (kidney) tests including your levels of creatinine and your estimated glomerular filtration rate (eGFR). This helps your doctor understand how well your kidneys are working. If you have kidney disease, the eGFR tells them what stage your kidney disease is at.    
• Liver tests including your levels of bilirubin, certain liver enzymes, and alkaline phosphatase. This helps your doctor to understand how well your liver is working and if you have any liver damage.
• Bone tests including your levels of calcium, phosphate, and alkaline phosphatase. This helps your doctor understand how healthy your bones and teeth are.  

If you’re over 40 you might also have an hBA1c test. This measures how well your body is processing sugar. This can help doctors diagnose diabetes or prediabetes. 

You might also be offered blood tests for syphilis and hepatitis as part of sexual health screening. If you need to be tested for other STIs this will require different tests, such as swabs.

Checking your blood chemistry

Blood chemistry looks at your blood cells.

• Red blood cell count. Red blood cells are important because they carry oxygen around your body. If you don’t have enough red blood cells then you have a condition called anaemia. Anaemia is also more common in people living with HIV than in the general population.
• Platelet count. This measures how many platelets you have. Platelets are cells which clot your blood. People with HIV often have fewer platelets than the general population. This is more likely if you aren’t taking anti-HIV treatment, or if your treatment isn’t working.
• White blood cell count. This measures how many white blood cells you have. These cells are part of the immune system and help fight infections. People with HIV often have fewer white blood cells than the general population. This is more likely if you aren’t taking anti-HIV treatment, or if your treatment isn’t working.

When all these cells are looked at together the test is called a ‘full blood count’. You might sometimes see this shortened to ‘FBC’. You should have a full blood count when you are first diagnosed with HIV and again when you start HIV treatment. You will usually also have a full blood count every year. You may have one more often if you are unwell, or if you are taking zidovudine (Retrovir, also in Combivir).

There is more information about on our page Blood problems and HIV.

Measuring your blood lipids

Blood lipid tests look at the amount and type of fat in your blood. We all need some fat in our blood, but the balance of fats is important. Having too much fat in your blood is linked to heart disease.

Your HIV clinic will measure your blood fats (lipids) because the levels can be affected by some anti-HIV medications. Lipid tests are sometimes called a ‘lipid panel’. A lipid panel includes:

• levels of HDL cholesterol
• levels of non-HDL cholesterol
• levels of triglycerides
• total cholesterol. This is a measure of the total level of cholesterol in your blood.

You should have your lipids measured when you are first diagnosed with HIV. If you are over the age of 40, if you smoke, or if your body mass index (BMI) is over 30, then they will be checked every year.

The results of your lipid tests can help you and your doctor choose the most suitable anti-HIV medications for you. Your doctor will also look at these levels to help them work out your risk of heart disease. There is more information about blood lipids on our page Cholesterol and HIV.

Testing for harmful side effects

Most people do not experience harmful side effects from their anti-HIV medication. However, your doctor might use a blood test to check for one of these side effects if you have certain signs or symptoms.

• Amylase. Abnormal levels of amylase can be a warning sign that you are at risk of a very serious condition called pancreatitis. This can be caused by lots of things, including some anti-HIV medications and some opportunistic infections.
• Creatine kinase. Raised levels of creatine kinase can sometimes signal that there is a problem with your muscles, perhaps caused by medication you’re taking.
• Lactate. Abnormal levels of lactate can be a sign of the rare, but very serious, side effect called lactic acidosis. This can be caused by NRTI medications such as emtricitabine and tenofovir disoproxil.

What are resistance tests?

When you are first diagnosed with HIV, you should have a resistance test. This provides information on resistance to HIV medications present in the type (strain) of HIV you have.

You will have a resistance test:

• before you start HIV treatment (if you didn’t have one when you were first diagnosed)
• if you need to change your anti-HIV medications because you have developed a detectable viral load again
• if there are signs that you might have been exposed to another strain of HIV (sometimes called reinfection or superinfection). These signs could include a sudden rise in your viral load or a sudden fall in your CD4 cell count.

Resistance tests can help you and your doctor decide which anti-HIV medications will work best for you. There's more information about resistance on our page Resistance to anti-HIV drugs.

Related information

You might find the following pages helpful:

• Getting the most out of your HIV clinic appointment
• Managing multiple health conditions