title: [Correlation and concordance of three HIV viral load techniques available in Colombia].
abstract: OBJECTIVE
  To compare the performance of three available technologies for Human Immunodeficiency Virus quantitation in Colombia.
  
  
  METHODS
  Samples from different areas of the Country were selected by convenience and underwent Human Immunodeficiency Virus quantitation using three methods: Versant bDNA 3.0 (Bayer), LCx HIV (Abbott) and Amplicor Monitor v1.5 (Roche). All samples were processed at the Centro de Análisis Molecular in Bogotá, Colombia. Results obtained with the three techniques were compared using linear regression. Additionally, the concordance between techniques was assessed calculating the unweighted kappa, the frequency of discordance according to cut-off points of clinical importance, and the frequency of differences exceeding 0.5 logs.
  
  
  RESULTS
  The correlation between techniques was highly significant, with an R2 higher than 0.97. The concordance was substantial, with unweighted kappas above 0.7. Nevertheless, the frequency of discordance for cut-off points of clinical importance and the frequency of differences exceeding 0.5 logs were considerable (8.8%-15.6% and 19.6%-36.3% respectively).
  
  
  CONCLUSIONS
  The three technologies for quantitation of viral load are adequate with high levels of correlation and concordance. However, because of the observed variability we recommend comparing a reading from one technique with another reading from the same technique when incorporating the results into clinical decision making.
authors.affiliation: Centro de Análisis Molecular, Bogotá, D.C., Colombia. patolaya@etb.net.co
authors.forename: Patricia
authors.initials: P
authors.lastname: Olaya
authors.forename: Carlos A
authors.initials: CA
authors.lastname: DíazGranados
mesh_terms: D003105:Colombia; D015658:HIV Infections / Q000175:diagnosis*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D019562:Viral Load
chemical_list: D011933:Reagent Kits, Diagnostic