title: Symptom screening rules to identify active pulmonary tuberculosis: Findings from the Zambian South African Tuberculosis and HIV/AIDS Reduction (ZAMSTAR) trial prevalence surveys.
abstract: BACKGROUND
  High tuberculosis (TB) burden countries should consider systematic screening among adults in the general population. We identified symptom screening rules to be used in addition to cough ≥2 weeks, in a context where X-ray screening is not feasible, aiming to increase the sensitivity of screening while achieving a specificity of ≥85%.
  
  
  METHODS
  We used 2010 Zambia South Africa Tuberculosis and HIV/AIDS Reduction (ZAMSTAR) survey data: a South African (SA) training dataset, a SA testing dataset for internal validation and a Zambian dataset for external validation. Regression analyses investigated relationships between symptoms or combinations of symptoms and active disease. Sensitivity and specificity were calculated for candidate rules.
  
  
  RESULTS
  Among all participants, the sensitivity of using only cough ≥2 weeks as a screening rule was less than 25% in both SA and Zambia. The addition of any three of six TB symptoms (cough <2 weeks, night sweats, weight loss, fever, chest pain, shortness of breath), or 2 or more of cough <2 weeks, night sweats, and weight loss, increased the sensitivity to ~38%, while reducing specificity from ~95% to ~85% in SA and ~97% to ~92% in Zambia. Among HIV-negative adults, findings were similar in SA, whereas in Zambia the increase in sensitivity was relatively small (15% to 22%).
  
  
  CONCLUSIONS
  High TB burden countries should investigate cost-effective strategies for systematic screening: one such strategy could be to use our rule in addition to cough ≥2 weeks.
authors.affiliation: Desmond Tutu TB Centre, Department of Pediatrics and Child Health, Stellenbosch University, Cape Town, South Africa.
authors.forename: M M
authors.initials: MM
authors.lastname: Claassens
authors.affiliation: The South African Department of Science and Technology/National Research Foundation Centre of Excellence in Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa.
authors.forename: C
authors.identifier: http://orcid.org/0000-0001-5154-1390
authors.initials: C
authors.lastname: van Schalkwyk
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Floyd
authors.affiliation: Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Zambia AIDS Related Tuberculosis Project, University of Zambia Ridgeway Campus, Lusaka, Zambia.
authors.forename: H
authors.initials: H
authors.lastname: Ayles
authors.affiliation: Desmond Tutu TB Centre, Department of Pediatrics and Child Health, Stellenbosch University, Cape Town, South Africa.
authors.forename: N
authors.initials: N
authors.lastname: Beyers
mesh_terms: D044383:Black People; D003141:Communicable Diseases / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology; D003371:Cough / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology; D004417:Dyspnea / Q000097:blood / Q000382:microbiology; D005260:Female; D005334:Fever / Q000097:blood / Q000453:epidemiology / Q000382:microbiology; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity; D013183:Sputum / Q000382:microbiology; D013542:Sweat / Q000382:microbiology; D014376:Tuberculosis / Q000097:blood / Q000453:epidemiology* / Q000382:microbiology; D015024:Zambia