Test features:
• performance characteristics (sensitivity and specificity) for the condition are known
• assume that the test has no direct adverse risk to the patient
benefit for treatment =
= (risk of adverse outcome from the disease in those untreated) - (risk of adverse outcome from the disease with treatment)
risk of treatment =
= (risk of significant adverse complication due to treatment)
testing threshold =
= ((1 - (specificity of test)) * (risk of treatment)) / (((1 - (specificity of test)) * (risk of treatment)) + ((sensitivity of test) * (benefit of test)))
test treatment threshold =
= ((specificity of test) * (risk of treatment)) / (((specificity of test) * (risk of treatment)) + ((1 - (sensitivity of test)) * (benefit of test)))
Interpretation:
• If the probability of disease is equal or more than the testing threshold and equal or less than the test treatment threshold, then the test should be done.
• If the probability of disease is less than the testing threshold, or more than the test treatment threshold, then the test should not be done.
