Was there an independent, blind comparison with a gold standard of diagnosis?
Was the diagnostic test evaluated in an appropriate spectrum of patients?
Was the gold standard applied regardless of the diagnostic test result?
Was the test validated in a second, independent group of patients?
2. What are the results?
Does this diagnostic test accurately distinguish between patients who do and do not have a specific disorder?
Sensitivity: Proportion of people with disease who have a positive test result.
Specificity: Proportion of people without disease who have a negative test result.
Likelihood Ratios: The likelihood that a given test result would be expected in a patient with the target disorder compared with the likelihood that this same result would be expected in a patient without the target disorder.
3. Are the results relevant to your patient?
Will the reproducibility of the test result and its interpretation be satisfactory in your clinical setting?
Are the study results applicable to the patients in your practice?
Are the study patients similiar to your own?
Do the test properties change, yield different likelihood ratios, due to disease severity or a different distribution of competing conditions?
Will the test results change your managment of the patient?
What are the test and treatment thresholds for this disease? Does the diagnostic test meet the treatment threshold?
Will your patient be better off as a result of the test?
Is the target disease, if left untreated, dangerous?
Do the benefits of the test outweigh its risks?
Does effective treatment exist?
Does the test yield useful information, otherwise unavailable, that leads to a change in management of your patient that is beneficial?
MedCalc 3000 is an electronic medical reference and analysis tool of calculators, decision trees, clinical criteria sets, equations, and unit and dose converters. Enter specificity, sensitivity or likelihood ratios as search terms.
This guide brings together a number of resources (videos, articles, and calculators) to aid clinicians in the interpretation of study results. Developed by Connie Schardt.
References
Critical appraisal questions come from the following sources:
Guyatt, G. Rennie, D. Meade, MO, Cook, DJ. Users’ Guide to Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd Edition 2008.
Sackett, DL, et al. Evidence Based Medicine: How to Practice and Teach EBM. 2nd ed. Edinburgh: Churchill Livingstone, 2000. BHSL Call Number: WB 102 E933 2000
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