Laboratory Assessment
There are some new recommendations as to how blood tests should be used to guide HIV treatment choices.- Drug Resistance Testing – The Panel recommends performing genotypic drug resistance testing for all treatment-naive (never been on HIV medications) patients entering into HIV care, regardless of whether antiretroviral therapy is to be started. This recommendation is based on the fact that people can become infected by resistant virus, meaning the newly infected person will have resistance despite never being on medications. Repeat testing may be considered later when HIV therapy is to be started.
A Step-By-Step Guide To HIV Resistance
- Tropism Assay – The Panel recommends tropism testing prior to the start of a CCR5 inhibitor, such
as maraviroc.
What is Tropism & Tropism Assay
- HLA-B Testing – The Panel recommends HLA-B testing prior to initiating abacavir therapy to reduce the risk of hypersensitivity reaction. Patients with the HLA-B genetic variant have been identified in studies as at risk for hypersensitivity reactions to Ziagen (abacavir). Those who test positive for HLA-B should not be prescribed Ziagen (abacavir) and the positive status should be recorded as an abacavir allergy in the patient’s medical record. When HLA-B screening is not readily available, it remains reasonable to initiate Ziagen (abacavir) with appropriate clinical counseling and monitoring for any signs of abacavir-associated hypersensitivity reaction.
When To Start Therapy
There are new recommendations as to when HIV medications should be started. These changes include the following.- The Panel recommends that antiretroviral therapy should be initiated in patients with history of an AIDS-defining illness or with a CD4 T-cell count <350 cells/mm3. The data supporting this recommendation is stronger for those with a CD4 T-cell count <200 cells/mm3 and with a history of AIDS than for those with CD4 T-cell counts between 200 and 350 cells/mm3.
What Are The AIDS Defining Illnesses
- The Panel also recommends treatment for the following groups regardless of CD4 T-cell count:
- pregnant patients
- patients with HIV associated kidney disease
- patients coinfected with hepatitis B when treatment for hepatitis B virus is indicated.
- The optimal time to initiate therapy in asymptomatic patients with CD4 T-cell count >350 cells/mm3 is not well defined. The decision of whether or not to start therapy in these patients should take into account the potential benefits and risks associated with therapy, other illnesses, and patient readiness and willingness to adhere to long-term treatment.
Source: DHHS Panel on Antiretroviral Guidelines for Adults and Adolescents; Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents.; 1 Dec 2007.
