Understanding Your Labs

Lab tests are very important tools your doctor uses to monitor your health. The information your doctor gets from your labs helps him or her decide how to treat you, monitor and evaluate side effects, and check the progress of your therapy.

Doctors perform several types of blood tests for people with HIV. "Baseline tests" will be performed so your doctor can get an idea of your health at the beginning of therapy. From this starting point, future lab tests will show how the disease and your medication are affecting your health. Without baseline testing, your doctor cannot tell whether you are doing better, worse, or the same with your treatment.

Complete Blood Count
One of the most common lab tests is the complete blood count or CBC. The CBC is a range of tests that measure different parts of the blood, such as the:

• White Blood Cells (WBC): count of the actual number of white blood cells present in the blood. If there is a rise in WBC count, this might mean infection, inflammation, or a problem with anemia
• Red Blood Cells (RBC): count of the actual number of red blood cells present in the blood. A decrease in RBCs could mean anemia, while an increase could be related to dehydration (such as from diarrhea)
• Platelets: count of the platelets or clotting cells present in the blood. A low or very high platelet count may mean excessive bleeding or clotting or other conditions

These blood measurements can signal how well your body is fighting HIV overall and can also help diagnose a bleeding disorder or a bone marrow disease. Since these blood cells are produced in your bone marrow, which can be affected by HIV infection, measuring them can help your doctor get an idea of how you are doing overall.

Blood Chemistry Tests
Blood chemistry tests are a good way of finding out how your organs are functioning by monitoring what they release into the blood. Some important ones include:

• Liver Enzyme Tests: measure levels of two important chemicals called enzymes produced by the liver: ALT (SGPT) and AST (SGOT). Liver disease can cause levels of these enzymes to increase. Liver tests are very important because the liver plays an important role in processing your HIV medicines and making sure they work effectively
• Kidney Function Tests: measure chemicals in the blood produced by the kidneys. It is important to monitor kidney function especially if you have HIV because the kidneys can be negatively affected by both the disease and the drugs used to treat it
• Lipid and Blood Sugar Tests: measure blood cholesterol and levels of blood sugar, also known as blood glucose. Antiretroviral drugs are sometimes associated with large increases in levels of these substances, making periodic checks necessary
• HIV-Specific Tests: measure levels of certain HIV-related substances in the blood; these tests include:
  
  
  • Viral load tests: Measures the amount of HIV in your blood and plays a role in determining whether and when you should start anti-HIV treatment or if you may need to change treatment
  • Lymphocyte tests: A count of the total number of CD4 T-cells in your sample of blood; a useful marker for when to start antiretroviral treatment and to predict the risk of complications such as infections
  • Resistance testing: Helps your doctor understand how your HIV infection might be changing, so he or she can adjust your medication appropriately

Your doctor will explain to you which tests you need and when you need them. If you have any questions about your blood tests or any other aspect of your treatment, be sure to discuss them with your doctor.