What bloodwork can assess immune status in an HIV (Human Immunodeficiency Virus) patient who has missed several months of antiretroviral therapy (ART) medications?

From the Guidelines

For an HIV patient who has missed several months of antiretroviral therapy, the most critical bloodwork to assess their immune status is a CD4 count and HIV viral load test, as recommended by the 2018 International Antiviral Society-USA panel 1. These two tests provide vital information about the patient's current immune function and viral control. The CD4 count measures T-helper lymphocytes, which are the primary cells infected by HIV, and indicates the strength of the immune system (normal range is typically 500-1500 cells/mm³). The HIV viral load quantifies the amount of virus in the blood, with the goal of treatment being to achieve an undetectable level (typically <20-50 copies/mL depending on the assay). Key points to consider when assessing an HIV patient who has missed several months of antiretroviral therapy include:

• CD4 count and HIV viral load test to assess immune function and viral control
• Complete blood count to assess for cytopenias
• Comprehensive metabolic panel to evaluate organ function
• Resistance testing if the viral load is detectable to determine if the virus has developed resistance to previous medications These tests are essential because medication interruption can lead to rapid viral rebound, CD4 decline, and potential development of drug resistance, as noted in the 2002 guidelines for using antiretroviral agents among HIV-infected adults and adolescents 1. Prompt reinitiation of antiretroviral therapy is typically recommended after these assessments, ideally using the patient's previous regimen if no resistance is suspected, or a new optimized regimen based on resistance testing results, as recommended by the 2018 International Antiviral Society-USA panel 1.

From the Research

Assessing Immune Status in HIV Patients

To assess the immune status of an HIV patient who has missed several months of antiretroviral therapy (ART) medications, the following bloodwork can be considered:

• CD4 count: This measures the number of CD4 T cells in the blood, which is an indicator of the health of the immune system 2, 3, 4, 5.
• Viral load: This measures the amount of HIV virus in the blood, which can indicate how well the virus is being controlled 2, 6, 3, 4, 5.
• HIV RNA: This measures the amount of HIV genetic material in the blood, which can indicate the level of viral activity 2, 3.

Key Considerations

When interpreting the results of these blood tests, the following considerations are important:

• A low CD4 count and high viral load can indicate a poorer response to ART and a higher risk of treatment failure 3, 4, 5.
• Patients with a higher viral load are more likely to experience a slower rate of achieving viral suppression 3.
• Non-adherence to treatment can increase the risk of transition from a healthy state to an AIDS state and death 4.
• Recovery from an AIDS state is likely to occur after one year of treatment, but a high viral load can increase the risk of immune deterioration and mortality 4.

Bloodwork Monitoring

Regular monitoring of CD4 count and viral load is essential to assess the effectiveness of ART and adjust treatment as needed:

• CD4 count should be monitored regularly to assess the health of the immune system 2, 3, 4, 5.
• Viral load should be monitored regularly to assess the level of viral activity and adjust treatment as needed 2, 6, 3, 4, 5.