TY - JOUR T1 - How to create PICO questions about diagnostic tests JF - BMJ Evidence-Based Medicine JO - BMJ EBM DO - 10.1136/bmjebm-2021-111676 SP - bmjebm-2021-111676 AU - Hendrika J Luijendijk Y1 - 2021/03/31 UR - http://ebm.bmj.com/content/early/2021/03/31/bmjebm-2021-111676.abstract N2 - PICOs are popular in medical teaching.1 The acronym stands for Patient (participant, problem or population), Intervention or exposure, Control (comparator) intervention or exposure, and Outcome. It is a useful tool to teach students how to formulate questions about the effect of a treatment in a testable way, and search for answers in the medical literature. A PICO is also helpful when designing and reporting a systematic review.Less obvious, but another strength of a PICO is its direct link with the 2×2 table of study results. The 2×2 table, or contingency table, is often used to present how often the outcomes (columns) occurred in the comparison groups (rows). The effect of the treatment on the risk of the outcome can then be calculated. Hence, the question and answer can be described very succinctly and intuitively in terms of a PICO and 2×2 table, respectively.However, composing a PICO for diagnostic questions is less straightforward. The most commonly used PICO reflects questions about the accuracy of a medical test, but does not align with the 2×2 table for a test accuracy study. Also, the field of diagnostic test research has evolved to comprise patient important outcomes. The question is then which effect the use of a test has on patient health, and the conventional PICO and 2×2 table apply.In this paper, I will illustrate how to make a PICO for both types of clinical questions about a medical test. First, I will present a PICO for a question about test accuracy that aligns with the 2×2 table of test accuracy studies. Next, I will show a PICO with a 2×2 table for a question about the effect of care with a test. The examples relate to breast cancer screening.One PICO for questions about medical tests has been advocated … ER -