title: A systematic review of the clinical validity of the Cologuard™ genetic test for screening colorectal cancer.
abstract: OBJECTIVE
  The aim of this study was to assess the available evidence on the validity, diagnostic accuracy and clinical utility of the multitarget DNA test in faeces (Cologuard™) for screening for colorectal cancer (CRC).
  
  
  METHODS
  A systematic review was performed by consulting MedLine, EMBASE and Web of Science to July 2014. Studies on diagnostic tests were selected that evaluated the test in asymptomatic adults who underwent CRC screening. The quality and risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool. The level of evidence was defined according to the National Institute for Health and Clinical Excellence. A qualitative synthesis was conducted.
  
  
  RESULTS
  A total of 299 literature references were identified, including 1 synthesis report and 5 diagnostic test studies. Three of the 5 studies had a case-control design in Sackett phase II and were of moderate quality, and 2 had a prospective design in Sacket phase III and were of high quality. The sensitivity for detecting CRC was greater than 90%, but only 40% for detecting advanced adenomas. The test provided conclusive diagnostic evidence to rule out CRC (negative likelihood ratio, LR-: 0.02-0.09), although it was not useful for ruling out advanced adenoma (LR-: 0.5-0.7).
  
  
  CONCLUSIONS
  The Cologuard™ test is a valid screening test for ruling out cancerous lesions but is suboptimal for ruling out precancerous lesions. There is no evidence in terms of mortality, survival or cost-effectiveness.
authors.affiliation: UGC Interniveles de Salud Pública de Granada, España. Electronic address: mariaa.onieva@gmail.com.
authors.forename: M Á
authors.initials: MÁ
authors.lastname: Onieva-García
authors.affiliation: Agencia de Evaluación de Tecnologías Sanitarias de Andalucía, Consejería de Salud de la Junta de Andalucía, Sevilla, España.
authors.forename: A
authors.initials: A
authors.lastname: Llanos-Méndez
authors.affiliation: Agencia de Evaluación de Tecnologías Sanitarias de Andalucía, Consejería de Salud de la Junta de Andalucía, Sevilla, España.
authors.forename: E
authors.initials: E
authors.lastname: Baños-Álvarez
authors.affiliation: Agencia de Evaluación de Tecnologías Sanitarias de Andalucía, Consejería de Salud de la Junta de Andalucía, Sevilla, España.
authors.forename: R
authors.initials: R
authors.lastname: Isabel-Gómez
keywords: Analysis of DNA mutations; Análisis de mutaciones de ADN; Colorectal cancer; Cribado; Cáncer colorrectal; Faeces; Heces; Revisión sistemática; Screening; Systematic review