October 7, 2019Fernando Chaves, MD
As the laboratory assumes an ever-more relevant role in health care, both from an economic and clinical perspective, it finds itself on the front lines in the global fight against HIV. After all, with effective drug regimens well established, the biggest challenge these days is getting those infected with HIV diagnosed as early and accurately as possible.
According to the World Health Organization, 37 million people worldwide are living with HIV. In the US, CDC estimates show more than 1.1 million people infected and that 162,500 of them— 15 percent—are undiagnosed and unaware of their status. This is a critical problem given that diagnosed patients now have options available that would allow them to enjoy a quality and duration of life not much different from non-infected individuals.
Undiagnosed HIV patients represent a serious challenge. From a public health perspective, nearly 40 percent of all new infections are transmitted by people who do not know they have the virus. From a clinical perspective, patients diagnosed early have favorable long-term outcomes, potentially staying healthy for years to come and lowering their chances of HIV-related illnesses.
By addressing this challenge, clinical laboratory managers have the power to save lives and reduce health care expenses. HIV tests vary greatly in performance characteristics, so clinical laboratory managers often have a critical choice to make.
To ensure that as few patients as possible go undiagnosed, laboratorians must select assays with high sensitivity and low risk of erroneous results caused by interference. This means not only using the CDC’s recommended assays and its algorithm for HIV testing, but also carefully reviewing individual assay performance.
While all fourth-generation assays allow detection of infections earlier, there are key differences even among those. Questions lab leaders should ask are:
- What is the analytical sensitivity of this assay?
- In seroconversion panels from recently infected patients, how many days did it take for this assay to become positive?
- How many different HIV genotypes is this assay capable of detecting?
- What safety mechanisms does the analyzer offer to detect common interferences such as hemolysis and lipemia?
These questions are becoming increasingly critical in the choice of the best HIV test. Why do they matter?
Use of pre-exposure prophylaxis is gaining wider adoption among high-risk populations, so infected patients may exhibit nearly undetectable levels of virus. In this situation, small differences in the limit of detection is no longer a technicality, but can rather mean the difference between life and death, impacting dozens of individuals who can potentially get infected by a person who receives a false negative result.
Additionally, international travel is increasing exponentially, meaning rare HIV genotypes currently not detectable by some existing tests may become more prevalent. Again, in this scenario, the ability of an assay to detect more genotypes can impact many lives.
Finally, HIV patients often have co-infections. A complete panel incorporating HCV, HBV, and STDs provides a one-stop testing solution for this high-risk population. Access to more complete infectious disease testing has immediate logistical benefit, helping laboratories increase operational efficiency. Through these more comprehensive panels, labs can reduce the number of analyzers needed, allowing managers to focus their resources where they matter the most, and giving them added flexibility.
It all adds up to this: Advances in technology combined with changes in the challenges posed by the HIV epidemic have created a new reality where the major opportunity medicine has to improve patients’ lives is now in the hands of laboratories and those who manage them.