title: Field Evaluation of Dried Blood Spots for HIV-1 Viral Load Monitoring in Adults and Children Receiving Antiretroviral Treatment in Kenya: Implications for Scale-up in Resource-Limited Settings.
abstract: The World Health Organization recommends viral load (VL) as the preferred method for diagnosing antiretroviral therapy failure; however, operational challenges have hampered the implementation of VL monitoring in most resource-limited settings. This study evaluated the accuracy of dried blood spot (DBS) VL testing under field conditions as a practical alternative to plasma in determining virologic failure (VF).
  
  
  
  From May to December 2013, paired plasma and DBS specimens were collected from 416 adults and 377 children on antiretroviral therapy for ≥6 months at 12 clinics in Kenya. DBSs were prepared from venous blood (V-DBS) using disposable transfer pipettes and from finger-prick capillary blood using microcapillary tubes (M-DBS) and directly spotting (D-DBS). All samples were tested on the Abbott m2000 platform; V-DBS was also tested on the Roche COBAS Ampliprep/COBAS TaqMan (CAP/CTM) version 2.0 platform. VF results were compared at 3 DBS thresholds (≥1000, ≥3000, and ≥5000 copies/mL) and a constant plasma threshold of ≥1000 copies/mL.
  
  
  
  On the Abbott platform, at ≥1000-copies/mL threshold, sensitivities, specificities, and kappa values for VF determination were ≥88.1%, ≥93.1%, and ≥0.82%, respectively, for all DBS methods, and it had the lowest percentage of downward misclassification compared with higher thresholds. V-DBS performance on CAP/CTM had significantly poorer specificity at all thresholds (1000%-33.0%, 3000%-60.9%, and 5000%-77.0%). No significant differences were found between adults and children.
  
  
  
  VL results from V-DBS, M-DBS, and D-DBS were comparable with those from plasma for determining VF using the Abbott platform but not with CAP/CTM. A 1000-copies/mL threshold was optimal and should be considered for VF determination using DBS in adults and children.
authors.affiliation: *US Centers for Disease Control and Prevention, Nairobi, Kenya; †US Centers for Disease Control and Prevention, Atlanta, GA; ‡Kenya Medical Research Institute, Nairobi, Kenya; §National HIV Reference Laboratory, Ministry of Health, Nairobi, Kenya; and ‖National AIDS and STI Control Program, Ministry of Health, Nairobi, Kenya.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Schmitz
authors.forename: Simon
authors.initials: S
authors.lastname: Agolory
authors.forename: Muthoni
authors.initials: M
authors.lastname: Junghae
authors.forename: Laura N
authors.initials: LN
authors.lastname: Broyles
authors.forename: Muthusi
authors.initials: M
authors.lastname: Kimeu
authors.forename: Joseph
authors.initials: J
authors.lastname: Ombayo
authors.forename: Mamo
authors.initials: M
authors.lastname: Umuro
authors.forename: Irene
authors.initials: I
authors.lastname: Mukui
authors.forename: Kennedy
authors.initials: K
authors.lastname: Alwenya
authors.forename: Moses
authors.initials: M
authors.lastname: Baraza
authors.forename: Kenneth
authors.initials: K
authors.lastname: Ndiege
authors.forename: Samuel
authors.initials: S
authors.lastname: Mwalili
authors.forename: Emilia
authors.initials: E
authors.lastname: Rivadeneira
authors.forename: Lucy
authors.initials: L
authors.lastname: Ngʼangʼa
authors.forename: Chunfu
authors.initials: C
authors.lastname: Yang
authors.forename: Clement
authors.initials: C
authors.lastname: Zeh
mesh_terms: D000328:Adult; D002648:Child; D059788:Dried Blood Spot Testing / Q000379:methods*; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D006295:Health Resources; D006801:Humans; D007630:Kenya; D008403:Mass Screening / Q000379:methods; D012367:RNA, Viral / Q000097:blood; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D017211:Treatment Failure; D019562:Viral Load / Q000379:methods*
chemical_list: D012367:RNA, Viral