title: Low specificity of determine HIV1/2 RDT using whole blood in south west Tanzania.
abstract: OBJECTIVE
  To evaluate the diagnostic performance of two rapid detection tests (RDTs) for HIV 1/2 in plasma and in whole blood samples.
  
  
  METHODS
  More than 15,000 study subjects above the age of two years participated in two rounds of a cohort study to determine the prevalence of HIV. HIV testing was performed using the Determine HIV 1/2 test (Abbott) in the first (2006/2007) and the HIV 1/2 STAT-PAK Dipstick Assay (Chembio) in the second round (2007/2008) of the survey. Positive results were classified into faint and strong bands depending on the visual appearance of the test strip and confirmed by ELISA and Western blot.
  
  
  RESULTS
  The sensitivity and specificity of the Determine RDT were 100% (95% confidence interval= 86.8 to 100%) and 96.8% (95.9 to 97.6%) in whole blood and 100% (99.7 to 100%) and 97.9% (97.6 to 98.1%) in plasma respectively. Specificity was highly dependent on the tested sample type: when using whole blood, 67.1% of positive results were false positive, as opposed to 17.4% in plasma. Test strips with only faint positive bands were more often false positive than strips showing strong bands and were more common in whole blood than in plasma. Evaluation of the STAT-PAK RDT in plasma during the second year resulted in a sensitivity of 99.7% (99.1 to 99.9%) and a specificity of 99.3% (99.1 to 99.4%) with 6.9% of the positive results being false.
  
  
  CONCLUSIONS
  Our study shows that the Determine HIV 1/2 strip test with its high sensitivity is an excellent tool to screen for HIV infection, but that--at least in our setting--it can not be recommended as a confirmatory test in VCT campaigns where whole blood is used.
authors: Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany. ikroidl@lrz.uni-muenchen.de
authors: Inge
authors: I
authors: Kroidl
authors: Petra
authors: P
authors: Clowes
authors: Wolfram
authors: W
authors: Mwalongo
authors: Lucas
authors: L
authors: Maganga
authors: Leonard
authors: L
authors: Maboko
authors: Arne L
authors: AL
authors: Kroidl
authors: Christof
authors: C
authors: Geldmacher
authors: Harun
authors: H
authors: Machibya
authors: Michael
authors: M
authors: Hoelscher
authors: Elmar
authors: E
authors: Saathoff
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002648:Child; D002675:Child, Preschool; D019937:Diagnostic Techniques and Procedures; D005189:False Positive Reactions; D005260:Female; D015658:HIV Infections / Q000097:blood* / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D015498:HIV-2 / Q000302:isolation & purification*; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013636:Tanzania / Q000453:epidemiology; D055815:Young Adult
chemical_list: D011933:Reagent Kits, Diagnostic