Table 2.

Clinical management of detectable viremia on ART

Machanism underlying detectable viremia on ART	Causes	Consequences	Management
Viral replication (ongoing new infection events)	Suboptimal adherence	Viral evolution	Adherence counselling
	Reduced ART concentration due to drug-to-drug interactions or limited absorbsion	Drug resistance	Therapeutic drug monitoring
		Increase in viremia and virological failure	HIV-1 genotyping from plasma***
		CD4+ T cells loss	ART regimen optimization
	Drug resistance	Risk of transmission
Viral expression from infected cells (virus production)	Latency reversal resulting in continuous virus production	No viral evolution	If all of the above not suggestive for viral replication:
		No drug resistance to current regimen	Monitoring of viremia over time
		Intermittent or stable viremia for months/years	Short course ART intensification
	Clonal expansion of cells carrying intact or defective proviruses	Stable CD4+ T cells	Characterization of virus in plasma with ultrasensitive assays
		Potential higher inflammation

^***Usually possible only with HIV-1 RNA levels above 400 copies/mL