title: Comparing HIV viral load assays and frequency of low level virological rebound in clinical practice.
abstract: Research suggests that some low-level virological rebound results occurring for no obvious clinical cause, in patients stable on antiretroviral therapy (ART), may be a consequence of the viral load assay used. We compared the relative frequency of clinically unexplained low-level virological rebound results when using the Roche HIV Taqman version-1 (CTM v1), the Roche HIV Taqman version-2 (CTM v2) and the Abbott RealTime (Abbott RT) assays in clinical practice. In all, 247 patients from our centre who had their viral loads measured by the three different assays over a period of 3 consecutive years (each assay used for a period of 1 year each) were included in the study. Low-level virological rebound was defined as <1000 copies/ml. Over similar time periods, there was significant discrepancy between the three assays when considering the proportion of clinically unexplained low-level virological rebound results in patients stable on ART: the CTM v2 assay produced the highest percentage (93%), CTM v1 much lower (65%) and Abbott RT even less (35%). There is further research required regarding what, if any, implications this has for patients who experience clinically unexplained low-level virological rebound on the more sensitive assays.
authors.affiliation: University of Edinburgh Medical School, Edinburgh, UK.
authors.forename: R
authors.initials: R
authors.lastname: Briggs
authors.affiliation: Microbiology and Virology Laboratories, Royal Infirmary of Edinburgh, NHS Lothian, Edinburgh, UK.
authors.forename: K
authors.initials: K
authors.lastname: Templeton
authors.affiliation: Chalmers Sexual Health Centre, NHS Lothian, Edinburgh, UK imali.fernando@live.co.uk.
authors.forename: I
authors.initials: I
authors.lastname: Fernando
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods; D012367:RNA, Viral / Q000032:analysis / Q000097:blood* / Q000235:genetics; D011933:Reagent Kits, Diagnostic / Q000821:virology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019914:Taq Polymerase / Q000378:metabolism*; D019562:Viral Load
chemical_list: D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic; D019914:Taq Polymerase
keywords: AIDS; HIV; antiretroviral therapy; blips; low-level virological rebound; treatment; viral load monitoring