Viral Load

• An HIV patient's viral load refers to the amount of the virus that is present in the blood when blood tests are performed. The virus can remain in the body even if the virus is not detected in a patient's blood work.
  
  

Reserves

• Viral reserves exist in the body where HIV can remain dormant and unaffected by antiretroviral medications. While the medications may kill the virus in the blood and cause blood tests to come back normal, the dormant virus can still return if treatment stops.
  
  

Electrolyte and Liver Function Tests

• Electrolyte and liver function tests are used to monitor the effectiveness of HIV medications and the progress of HIV infection even when viral loads are low or undetectable. These tests do not measure the amount of HIV in an individual's system, however.
  
  

CD4 Immune Cell Count

• CD4 immune cell counts measure the number of CD4 cells that are in the blood, as these are the primary cells in which HIV replicates. If CD4 cell counts begin to drop it is generally because of an increasing amount of HIV reproducing in the cells.
  
  

Other Sexually Transmitted Diseases

• HIV infection can be affected by the presence of other sexually transmitted diseases (STDs). Even if a patient has an undetectable viral load, acquiring an STD can cause HIV levels in the blood to increase significantly and result in a major resurgence of the virus.