Strictly speaking, there is a difference between diagnostic yield and diagnostic accuracy.
Diagnostic yield is the likelihood that a test or procedure will provide the information needed to establish a diagnosis.
Diagnostic accuracy is the degree to which a measurement, or an estimate based on measurements, represents the true value of the attribute being measured. Or it measures how correct a diagnostic test truly identifies and excludes a given condition.
In the field of biopsy or histopathology, here are the measures:
Diagnostic yield examined the proportion of biopsies producing specific pathological diagnosis. It can be calculated by the number of biopsies producing specific pathological diagnosis, divided by total biopsies carried out.
Diagnostic accuracy examined the concordant rate of the biopsy result and final diagnosis. It can be calculated by the number of biopsies giving same diagnosis as correlated by operative findings or clinco-radiological follow-up, divided by total biopsies carried out.
In determining the value of a diagnostic test, it is recommended that one considers both the diagnostic yield and diagnostic accuracy of the test based on track record in actual practice and in literature.
For example, in the hand of an expert surgeon who does needle evaluation and aspiration biopsy of dominant breast mass, the diagnostic yield may be 95% and the diagnostic accuracy may be 97%. In such a situation, needle evaluation and aspiration biopsy may be preferred over a core needle biopsy or open biopsy.