title: Analytical performance of an automated assay quantifying HIV-1 from dried blood spots.
abstract: BACKGROUND
  Performance of an automated sample preparation and viral load quantification for HIV-positive dried blood spots (DBS) on the Siemens VERSANT(®) kPCR Molecular System has been previously demonstrated with clinical samples.
  
  
  OBJECTIVE
  Evaluation of the analytical performance of the automated assay using HIV-positive DBS prepared from a dilution series.
  
  
  METHODS
  Over 300 DBS of HIV-1 nucleic acids from a dilution series in lysed whole blood (322 copies/mL to over 1.6 × 10(7)copies/mL) were spotted onto Whatman 903 cards and analyzed to evaluate analytical performance. Cross contamination was examined with a checkerboard pattern of 82 alternating negative and 1 × 10(6)copies/mL samples.
  
  
  RESULTS
  Analytical sensitivity evaluation with a single 50 μL spot demonstrated a limit of detection (LoD) of 866 copies/mL. Above the LoD, linearity (difference between linearized and observed mean values) was within ± 0.10 log, and accuracy (difference between expected and observed mean values) was within ±0.18log. Imprecision for dilution series levels more than two-fold above the LoD was measured as 20% to 27% CV of quantification. No cross contamination was observed.
  
  
  CONCLUSIONS
  The HIV-1 DBS Assay performed similarly to the VERSANT HIV-1 RNA 1.0 Assay (kPCR) in assay linearity, accuracy, and imprecision. The assay was sensitive enough to run single 50μL spots and used an unmodified VERSANT(®) SP Module with only a 30 min incubation prior to automated sample preparation. DBS-specific assay calibrators and controls, expressly formulated for easy frozen storage and identical processing to samples, were employed.
authors.affiliation: Siemens Healthcare Diagnostics, Berkeley, CA 94710, USA.
authors.forename: Felix
authors.initials: F
authors.lastname: Kleshik
authors.forename: Jesse
authors.initials: J
authors.lastname: Brooks
authors.forename: Carlo
authors.initials: C
authors.lastname: Cosenza
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Battersby
mesh_terms: D057205:Automation, Laboratory / Q000379:methods*; D003890:Desiccation; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D019562:Viral Load / Q000379:methods*