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Applied Evidence Based Medicine


  • Understand how to use PICO to formulate a diagnosis question
  • Learn how to use the TRIP Database to search for answers to your diagnosis question
  • Become familiar with resources for understanding diagnosis studies, as well as point-of-care diagnostic tools

PICO for Diagnosis Questions

When using PICO to frame a diagnosis question, the P is the patient or problem; the I is the particular diagnostic method, test, procedure, tool, or screening instrument you're interested in; the is an alternative diagnostic tool, such as the current gold standard; and the O is the sensitivity and specificity of the diagnostic tool (but you generally don't need to include the outcome in your database search).

Here are a couple of examples of scenarios requiring a diagnostic tool and how you would break them down using PICO:


Scenario 1: You're on a team reviewing cervical cancer screening guidelines in your region. The most commonly used test is the pap test, which detects abnormal cells, but not the HPV virus itself. In recent years, tests have been developed that detect the HPV virus. You want to know what the latest evidence says about using the HPV test versus the pap test, or whether they should sometimes be used in combination.

P: cervical cancer

I: HPV test

C: pap smear or pap test

O: effectiveness of each tool; cost may also be of interest when setting policy (it's not necessary to search for these outcomes)

Clinical Question: Is the HPV test or the pap test more effective at detecting cervical cancer?


Scenario 2: You're a family physician in a community that you suspect has relatively high rates of alcohol use. You're particularly concerned about levels of problem drinking in your adolescent patients and are looking for a quick screening tool that you can use to easily identify patients with potential problems. You're familiar with the Alcohol Use Identification Test (AUDIT), but you've also heard of another instrument called the Problem Oriented Screening Instrument for Teenagers Substance Use/Abuse Scale (POSIT). You want to know how the two compare.

P: adolescents with high rates of alcohol use



O: effectiveness of each tool (it's not necessary to search for this outcome)

Clinical Question: Is AUDIT or POSIT more effective at identifying adolescents with high rates of alcohol use?

Using the TRIP Database to Answer a Diagnosis Question

Try out the above clinical questions in both TRIP and PubMed Clinical Queries (using the diagnosis filter). Which resource gives you better results?

Resources for Understanding Diagnosis Studies

Point-of-Care Diagnostic Tools Subscribed to by the UCalgary Library

Free Diagnosis Websites and Mobile Apps