title: [Validity of the clinical diagnosis of the basal cell carcinoma in primary health care].
abstract: OBJECTIVE
  To measure the validity of the clinical diagnosis of the basal cell carcinoma (BCC) in primary care.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Primary health care Area 8 in Madrid. PATIENTS AND ITNERVENTIONS: A study was carried out on a group of patients that had been histopathologically diagnosed of BCC and on another that had received any of the most frequent differential diagnoses. A sample estimate was made with the most unfavourable situation of a sensitivity and a specificity of 50%, a precision of 5%, a confidence of 95% and losses of 20%. It was estimated that 962 cases were necessary.
  
  
  METHODS
  The histopathological diagnosis (gold standard) were compared to the clinical diagnosis. Sensitivity, specificity, predictive values, likelihood ratios and global value were estimated.
  
  
  RESULTS
  963 patients were included of which 7.6% were lost 890 cases were studied, 491 with BCC and 399 with differential diagnoses. The most frequent location of BCC was the face (65.8%). Sensitivity was 27.5% (95% CI, 23.531.5%), specificity 90.5% (95% CI, 87.5-93.5%), the global value of 55.7% (95% CI, 52.7-58.7%), positive predictive value, 78.0% (95% CI, 72.084.0%) and negative predictive value 50,3% (95% CI, 46.354.3%).
  
  
  CONCLUSIONS
  Validity was moderate with low sensitivity and very low positive predictive value, the latter estimated for its expected prevalence. The clinical diagnosis of BCC in primary health care must be complemented with other diagnostic tests.
authors.affiliation: Unidad de Medicina Preventiva, Fundación Hospital Alcorcón, Departamento de Ciencias de la Salud, Universidad Rey Juan Carlos, Madrid, Spain. grodriguez@fhalcorcon.es
authors.forename: G
authors.initials: G
authors.lastname: Rodríguez Caravaca
authors.forename: J
authors.initials: J
authors.lastname: García-Cruces Méndez
authors.forename: S
authors.initials: S
authors.lastname: Hobson
authors.forename: F
authors.initials: F
authors.lastname: Rodríguez Caravaca
authors.forename: M
authors.initials: M
authors.lastname: Villar Del Campo
authors.forename: M
authors.initials: M
authors.lastname: González Mosquera
mesh_terms: D000368:Aged; D002280:Basal Cell Carcinoma / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care
vernacular_title: Validez del diagnóstico clínico de carcinoma basocelular en atención primaria.