Long-term resolution of viral breakthrough after changing HIV viral load assay

Background: Viral load (VL) measurement assays differ in their sensitivity with polymerase chain reaction assays (PCR) being more sensitive than branched DNA (bDNA) assays. We evaluated virologic outcomes of patients and physicians' response to increased VL after a switch from bDNA to PCR assay. Method: Retrospective, case-control study on 65 HIV+ patients receiving highly active antiretroviral therapy (HAART). Cases included patients with undetectable VL by bDNA that became detectable after the switch; controls were patients that remained undetectable. Records were reviewed up to 1 year after the switch. Results: A total of 58.5% patients had detectable VL after the switch. Repeat VL testing and resistance testing were ordered in 15.4% and 23.1% of these patients, respectively. By 1 year, VL was undetectable in 82.8% of cases and 92% of controls (P =.30), without change in HAART. Conclusion: Transient viremia after changing VL assay reflects the different sensitivity of these assays with no impact on patients' outcomes compared to controls.