Ultrasensitive HIV-1 Viral Load Quantification

Throughout the study period, participants’ viral load was monitored every 3 months using the Abbott RealTime HIV-1 assay (Abbott Molecular Inc.). In order to quantify plasma viraemia under the detection limit of standard methodologies (50 HIV-1 RNA copies/mL), cryopreserved plasma samples were analysed using an ultrasensitive viral load test.¹³ (link) Briefly, up to 7.5 mL of plasma was ultracentrifuged prior to extraction and quantification of viral RNA using the Abbott RealTime HIV-1 assay and the Abbott m2000rt instrument. An in-house calibration curve set (range 10¹–10³ copies/mL), which had previously been validated using a standard HIV-1 RNA control from the WHO, was used as a reference.