GRADE guidelines: 21 part 1. Study design, risk of bias, and indirectness in rating the certainty across a body of evidence for test accuracy.

• Schünemann HJ Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada. Electronic address: schuneh@mcmaster.ca.
• Mustafa RA Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, University of Kansas Medical Center, Kansas City, KS, USA.
• Brozek J Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
• Steingart KR Department of Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
• Leeflang M Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical Centers, Room J1b-214, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
• Murad MH Division of Preventive Medicine, Mayo Clinic, 200 1st Street SW, Rochester, MN 55902, USA.
• Bossuyt P Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical Centers, Room J1b-214, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
• Glasziou P CREBP, Faculty Health Science & Medicine, Bond University, Gold Coast QLD 4229, Australia.
• Jaeschke R Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
• Lange S Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen, Institute for Quality and Efficiency in Health Care (IQWiG), Im Mediapark 8, 50670 Köln, Germany Cologne, Germany.
• Meerpohl J Institute for Evidence in Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany; Cochrane Germany, Cochrane Germany Foundation, Freiburg, Germany.
• Langendam M Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical Centers, Room J1b-214, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
• Hultcrantz M Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU), S:t Eriksgatan 117, SE-102 33, Stockholm, Sweden.
• Vist GE Norwegian Knowledge Centre for the Health Services, PO Box 7004, St Olavs Plass, 0130 Oslo, Norway.
• Akl EA Department of Internal Medicine, American University of Beirut, Riad-El-Solh Beirut, Beirut 1107 2020, Lebanon.
• Helfand M Oregon Evidence-based Practice Center, Oregon Health & Science University, Portland VA Medical Center, Portland, OR, USA.
• Santesso N Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
• Hooft L Cochrane Netherlands/Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
• Scholten R Cochrane Netherlands/Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands.
• Rosen M Swedish Agency for Health Technology Assessment and Assessment of Social Services (SBU), S:t Eriksgatan 117, SE-102 33, Stockholm, Sweden.
• Rutjes A Clinical Trial Unit (CTU) Bern, Institute of Primary Health Care, University of Bern, Bern, Switzerland.
• Crowther M Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.
• Muti P Department of Oncology, McMaster University, 711 Concession Street, Hamilton, Ontario L8V1C3, Canada.
• Raatz H University of Basel, Klingelbergstrasse 61, CH-4056 Basel, Switzerland; Kleijnen Systematic Reviews Ltd, 6 Escrick Business Park, Escrick, York YO19 6FD, UK.
• Ansari MT School of Epidemiology and Public Health, Faculty of Medicine, Ottawa, Canada.
• Williams J Duke University Medical Center and Durham Veterans Affairs Center for Health Services Research in Primary Care Durham, NC 27705, USA.
• Kunz R Basel Institute of Clinical Epidemiology, University Hospital Basel, Hebelstrasse 10, Basel 4031, Switzerland.
• Harris J Harris Associates, 386 Richardson Way, Mill Valley, CA 94941, USA.
• Rodriguez IA Clinical Biostatistics Unit, Hospital Universitario Ramón y Cajal, IRYCIS, CIBER of Epidemiology and Public Health, Madrid, Spain; Centro de investigación en Salud Pública y Epidemiología Clínica, Facultad de Ciencias de la Salud Eugenio Espejo, Universidad UTE, Quito, Ecuador.
• Kohli M Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4, Canada.
• Guyatt GH Department of Health Research Methods, Evidence, and Impact, McMaster GRADE Centre, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada; Department of Medicine, University of Kansas Medical Center, Kansas City, KS, USA.

Certainty of evidence

Diagnosis

Diagnostic accuracy

GRADE

Test accuracy

Tests