title: Can HIV reverse transcriptase activity assay be a low-cost alternative for viral load monitoring in resource-limited settings?
abstract: OBJECTIVE
  To evaluate the performance and cost of an HIV reverse transcriptase-enzyme activity (HIV-RT) assay in comparison to an HIV-1 RNA assay for routine viral load monitoring in resource limited settings.
  
  
  METHODS
  A cohort-based longitudinal study.
  
  
  METHODS
  Two antiretroviral therapy (ART) centres in Karnataka state, South India, providing treatment under the Indian AIDS control programme.
  
  
  METHODS
  A cohort of 327 HIV-1-infected Indian adult patients initiating first-line ART.
  
  
  METHODS
  Performance and cost of an HIV-RT assay (ExaVir Load V3) in comparison to a gold standard HIV-1 RNA assay (Abbott m2000rt) in a cohort of 327 Indian patients before (WK00) and 4 weeks (WK04) after initiation of first-line therapy.
  
  
  RESULTS
  Plasma viral load was determined by an HIV-1 RNA assay and an HIV-RT assay in 629 samples (302 paired samples and 25 single time point samples at WK00) obtained from 327 patients. Overall, a strong correlation of r=0.96 was observed, with good correlation at WK00 (r=0.84) and at WK04 (r=0.77). Bland-Altman analysis of all samples showed a good level of agreement with a mean difference (bias) of 0.22 log10copies/mL. The performance of ExaVir Load V3 was not negatively affected by a nevirapine/efavirenz based antiretroviral regimen. The per test cost of measuring plasma viral load by the Abbott m2000rt and ExaVir Load V3 assays in a basic lab setting was $36.4 and $16.8, respectively.
  
  
  CONCLUSIONS
  The strong correlation between the HIV-RT and HIV-1 RNA assays suggests that the HIV-RT assay can be an affordable alternative option for monitoring patients on antiretroviral therapy in resource-limited settings.
  
  
  BACKGROUND
  ISRCTN79261738.
authors.affiliation: Division of Clinical Virology, Department of Microbiology, St. John's Medical College, Bangalore, India.
authors.forename: Soham
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Division of Clinical Virology, Department of Microbiology, St. John's Medical College, Bangalore, India.
authors.forename: Riya
authors.initials: R
authors.lastname: Palchaudhuri
authors.affiliation: Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ujjwal
authors.initials: U
authors.lastname: Neogi
authors.affiliation: Division of Clinical Virology, Department of Microbiology, St. John's Medical College, Bangalore, India.
authors.forename: Hiresave
authors.initials: H
authors.lastname: Srinivasa
authors.affiliation: Department for International Health, University of Tampere School of Medicine, Tampere, Finland.
authors.forename: Per
authors.initials: P
authors.lastname: Ashorn
authors.affiliation: Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden.
authors.forename: Ayesha
authors.initials: A
authors.lastname: De Costa
authors.affiliation: Cavidi AB, Uppsala, Sweden.
authors.forename: Clas
authors.initials: C
authors.lastname: Källander
authors.affiliation: Department of Pediatrics, St John's Medical College Hospital, Bangalore, India.
authors.forename: Anita
authors.initials: A
authors.lastname: Shet
mesh_terms: D019380:Anti-HIV Agents / Q000627:therapeutic use; D003365:Costs and Cost Analysis; D024882:Drug Resistance, Viral; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000379:methods; D015658:HIV Infections / Q000188:drug therapy / Q000201:enzymology / Q000821:virology*; D054303:HIV Reverse Transcriptase / Q000378:metabolism*; D015497:HIV-1; D006801:Humans; D007194:India; D008137:Longitudinal Studies; D008507:Medically Underserved Area; D019095:Point-of-Care Systems; D012367:RNA, Viral / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D019562:Viral Load / Q000379:methods*
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase
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