Doctors can measure the number or proportion of certain types of cells in an AIDS patient’s blood to see whether and how rapidly the disease is progressing, or whether certain treatments are helping the patient. These cell count tests include:
Complete blood count (CBC):
A CBC is a routine analysis performed on a sample of blood taken from the patients. The measurements taken in a CBC include a white blood cell count (WBC), a red blood cell count (RBC), the red cell distribution width, the hematocrit and the amount of haemoglobin.
Specific AIDS- related signs in a CBC include a low hematocrit, a sharp decrease in the number of blood platelets, and a low level of neutrophils.
Absolute CD4+ lymphocytes:
Since HIV targets CD4 + lymphocytes, their number in the patient’s blood can be used to track the course of the infection. This blood cell count is considered the most accurate indicator for the presence of an opportunistic infection in an AIDS patient.
An absolute count below 200-300 CD4 + lymphocytes in 1 cubic millimeter (mm3) of blood indicates that the patient is vulnerable to some opportunistic infections.
CD4+ lymphocyte percentage:
Some doctors think that this is a more accurate test than the absolute count because the percentage does not depend on a manual calculation of the number of types of different white blood cells.
HIV Viral load Tests:
Another type of blood test for monitoring AIDS patients is the viral load test. It supplements the CD4 + count, which can tell the doctor the extent of the patient’s loss of immune function, but not the speed of HIV replication in the body. The viral load test is based on PCR techniques and can measure the number of copies of HIV nucleic acids.
Oral HIV Tests:
Scientists have developed oral HIV tests that can be conducted with saliva samples. It is considered as an excellent alternative to blood sample testing.
Rapid HIV Tests:
A finger-stick test that can be read quickly from a whole blood sample had shown promising results in the fall of 2003.
Another test, called the VScan test kit, requires no refrigeration or electricity and can safely be stored at room temperature. Even if the positive results must be confirmed by ELISA or Western blotting, an accurate initial rapid test can help screen populations for HIV antibodies.
Beta 2-Microglobulin (BETA2M):
Beta-microglobulin is a protein found on the surface of all human cells with a nucleus. It is released into the blood when a cell dies. Although rising blood levels of P2M are found in patients with cancer and other serious diseases, a rising p2M blood level can be used to measure the progression of AIDS.
Genotypic drug resistance Test:
Genotypic testing can help determine whether specific gene mutations, common in people with HIV, are causing drug resistance and drug failure.
The test looks for specific genetic mutations within the virus that are known to cause resistance to certain drugs used in HIV treatment.
For example the drug 3TC, also known as lamivudine (Epivir), is not effective against strains of HIV that have a mutation at a particular position on the reverse transcriptase protein – amino acid 184 – known as M184V (M-V, methionine to valine).
So if the genotypic resistance test shows a mutation at position M184V, it is likely the person is resistant to 3TC and not likely to respond to 3TC treatment. Genotypic tests are only effective if the person is already taking antiviral medication and if the viral load is greater than 1,000 copies per milliliter (ml) of blood.
Phenotypic drug resistance Testing:
Phenotypic testing directly measures the sensitivity of a patient’s HIV to particular drugs and drug combinations.
Phenotypic testing is a more direct measurement of resistance than genotypic testing. Unlike genotypic testing, phenotypic testing does not require a high viral load but it is recommended that persons already be taking antiretroviral drugs.