title: Evaluation of the 2007 WHO guideline to improve the diagnosis of tuberculosis in ambulatory HIV-positive adults.
abstract: BACKGROUND
  In 2007 WHO issued a guideline to improve the diagnosis of smear-negative and extrapulmonary tuberculosis (EPTB) in HIV-positive patients. This guideline relies heavily on the acceptance of HIV-testing and availability of chest X-rays.
  
  
  RESULTS
  Cohort study of TB suspects in four tuberculosis (TB) clinics in Phnom Penh, Cambodia. We assessed the operational performance of the guideline, the incremental yield of investigations, and the diagnostic accuracy for smear-negative tuberculosis in HIV-positive patients using culture positivity as reference standard. 1,147 (68.9%) of 1,665 TB suspects presented with unknown HIV status, 1,124 (98.0%) agreed to be tested, 79 (7.0%) were HIV-positive. Compliance with the guideline for chest X-rays and sputum culture requests was 97.1% and 98.3% respectively. Only 35 of 79 HIV-positive patients (44.3%) with a chest X-ray suggestive of TB started TB treatment within 10 days. 105 of 442 HIV-positive TB suspects started TB treatment (56.2% smear-negative pulmonary TB (PTB), 28.6% smear-positive PTB, 15.2% EPTB). The median time to TB treatment initiation was 5 days (IQR: 2-13 days), ranging from 2 days (IQR: 1-11.5 days) for EPTB, over 2.5 days (IQR: 1-4 days) for smear-positive PTB to 9 days (IQR: 3-17 days) for smear-negative PTB. Among the 34 smear-negative TB patients with a confirmed diagnosis, the incremental yield of chest X-ray, clinical suspicion or abdominal ultrasound, and culture was 41.2%, 17.6% and 41.2% respectively. The sensitivity and specificity of the algorithm to diagnose smear-negative TB in HIV-positive TB suspects was 58.8% (95%CI: 42.2%-73.6%) and 79.4% (95%CI: 74.8%-82.4%) respectively.
  
  
  CONCLUSIONS
  Pending point-of-care rapid diagnostic tests for TB disease, diagnostic algorithms are needed. The diagnostic accuracy of the 2007 WHO guideline to diagnose smear-negative TB is acceptable. There is, however, reluctance to comply with the guideline in terms of immediate treatment initiation.
authors.affiliation: Institute of Tropical Medicine, Antwerp, Belgium. okoole@itg.be
authors.forename: Olivier
authors.initials: O
authors.lastname: Koole
authors.forename: Sopheak
authors.initials: S
authors.lastname: Thai
authors.forename: Kim Eam
authors.initials: KE
authors.lastname: Khun
authors.forename: Reaksmey
authors.initials: R
authors.lastname: Pe
authors.forename: Johan
authors.initials: J
authors.lastname: van Griensven
authors.forename: Ludwig
authors.initials: L
authors.lastname: Apers
authors.forename: Jef
authors.initials: J
authors.lastname: Van den Ende
authors.forename: Tan Eang
authors.initials: TE
authors.lastname: Mao
authors.forename: Lutgarde
authors.initials: L
authors.lastname: Lynen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000553:Ambulatory Care; D005260:Female; D006679:HIV Seropositivity / Q000150:complications* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017410:Practice Guidelines as Topic / Q000592:standards*; D013902:Radiography, Thoracic; D016896:Treatment Outcome; D014376:Tuberculosis / Q000150:complications* / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014944:World Health Organization; D055815:Young Adult