title: Criteria for monitoring tests were described: validity, responsiveness, detectability of long-term change, and practicality.
abstract: OBJECTIVE
  To describe how evidence from trials and cohort studies may be used to guide choice of test for monitoring patients with chronic disease.
  
  
  METHODS
  Exploration of potential criteria for choosing the best monitoring test. Criteria are defined and options for assessment measures for test performance on each criterion discussed.
  
  
  RESULTS
  Monitoring in clinical practice occurs in three main phases: before treatment, response to treatment, and long-term monitoring. Four important criteria may be used to choose the best test for monitoring a patient in each of these phases. Clinical validity describes the ability of the test to predict the clinically relevant outcome that we are trying to control or prevent. Responsiveness describes how much the test changes in response to an intervention relative to background random variation. Detectability of long-term change describes the size of changes in the test over the long term relative to background random variation. Practicality describes the ease of use, invasiveness, and cost of the test. Test performance generally requires longitudinal data from trial and/or cohort studies using statistical methods such as those discussed.
  
  
  CONCLUSIONS
  Four specific criteria can help clinicians inform evidence-based decisions on which monitoring test to use.
authors.affiliation: Centre for Research in Evidence-Based Practice (CREBP), Bond University, Gold Coast, QLD 4229, Australia; Screening and Diagnostic Test Evaluation Program (STEP), School of Public Health, Building A27, University of Sydney, Sydney, NSW 2006, Australia. Electronic address: katy.bell@sydney.edu.au.
authors.forename: Katy J L
authors.initials: KJ
authors.lastname: Bell
authors.affiliation: Centre for Research in Evidence-Based Practice (CREBP), Bond University, Gold Coast, QLD 4229, Australia.
authors.forename: Paul P
authors.initials: PP
authors.lastname: Glasziou
authors.affiliation: School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hayen
authors.affiliation: Screening and Diagnostic Test Evaluation Program (STEP), School of Public Health, Building A27, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Les
authors.initials: L
authors.lastname: Irwig
mesh_terms: D002908:Chronic Disease; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D003955:Diagnostic Tests, Routine / Q000379:methods* / Q000592:standards; D019317:Evidence-Based Medicine; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods* / Q000592:standards
keywords: Biological markers; Chronic disease; Diagnostic tests; Disease management; Reproducibility of results; Statistical models