HIV Testing

CD4 Baseline Testing

CD4 cell count testing at baseline for all people living with HIV

The 2017 WHO guidelines point out that CD4 cell count testing at baseline for all people living with HIV remains important, because relying on clinical staging alone risks missing substantial numbers of people living with HIV with severe immune suppression¹.

In a study from Kenya, Malawi, Uganda, and Zimbabwe, almost half the people with CD4 count <100 cells/µl were classified as having WHO clinical stage 1 or 2 disease¹. Hence, identifying people with advanced HIV disease who are eligible for elements of a package of care requires CD4 cell count testing¹.

All patients entering or re-entering care should receive a CD4 test at treatment baseline and as clinically indicated for patients with unstable or advanced HIV disease².

Identification of Advanced HIV Disease

Definition of advanced HIV disease

People presenting with advanced HIV disease are at high risk of death. The 2017 WHO guidelines define advanced HIV disease as follows³:

1. For adults, adolescents, and children older than five years, advanced HIV disease is defined as CD4 cell count <200 cells/µl or WHO stage 3 or a 4 event.
2. All children younger than five years old with HIV are considered as having advanced HIV disease.
3. A severely immunosuppressed adult is defined as having a CD4 cell count <50 cells/µl.

People presenting with advanced HIV disease are at high risk of death, even after starting ART (Antiretroviral Therapy), with the risk increasing with decreasing CD4 cell count, especially with CD4 cell count <100 cells/µl⁴. Relying on clinical staging alone risks missing substantial numbers of people living with HIV with severe immune suppression¹.

Advanced HIV disease package of care

People with advanced HIV disease are defined as those presenting to care with a CD4 count below 200 cells/µl or WHO disease stages 3 and 4.

The package of care for these people should include the following⁵:

1. Rapid initiation of ART (once the risk of immune reconstitution inflammatory syndrome [IRIS] is ruled out);
2. Systematic screening for Cryptococcus antigen;
3. Screening and treatment for tuberculosis (TB) or isoniazid preventive treatment (IPT) as indicated;
4. Screening for toxoplasmosis and Co-trimoxazole (CTX) prophylaxis; and
5. Intensive follow-up³.

Laboratory & Diagnostic Services

Effective laboratory and diagnostic services

Even in settings with full access to viral load testing, CD4 cell count testing capability will continue to be needed as part of HIV programs for baseline risk and other clinical assessments. Depending on the context, as the transition to viral load monitoring from CD4 count testing for initiation and monitoring progresses, programs may wish to consider centralizing the continued use of CD4 count testing¹⁷.

Continue to the next section of Beckman Coulter Life Sciences’ “Twelve Steps to CD4 Testing.”