What is QUADAS-C for?

• QUADAS-C is designed to assess risk of bias of a test comparison in comparative accuracy studies - primary studies that compare the accuracy of two or more index tests

What is QUADAS-C not intended to do?

• QUADAS-C does not assess risk of bias in test comparisons made between studies, each evaluating a single index test (also called between-study or indirect comparisons)
• QUADAS-C does not assess concerns regarding applicability

What does it mean that QUADAS-C is an extension to QUADAS?

• QUADAS-C was originally developed as an extension of QUADAS-2. 
• QUADAS-C cannot be used alone and must be used alongside the main QUADAS tool. Now that QUADAS-3 is available we recommend using QUADAS-C alongside QUADAS-3.
• Adaptation is needed before it can be applied alongside QUADAS-3. The QUADAS-3 E&E document provides guidance on how to apply QUADAS-C alongside QUADAS-3

How to cite QUADAS-C

QUADAS-c was published in Annals of Internal Medicine in October 2021.  To cite the QUADAS-C tool use:

Yang B, Mallett S, Takwoingi Y, Davenport CF, et al. QUADAS-C: A Tool for Assessing Risk of Bias in Comparative Diagnostic Accuracy Studies. Ann Intern Med. 2021 Nov;174(11):1592-1599. doi: 10.7326/M21-2234.