The recent Ebola death in Dallas highlights the point that many have made recently. The Society to Improve Diagnosis in Medicine seeks to place diagnostic error and accuracy at the forefront of medical quality. Bob Wachter’s wonderful editorial in USA Today – What Ebola error in Dallas shows: Column highlights the problem and some causes of diagnostic error.

We have politicians and administrators championing incentives to improve quality, but they are missing a key point. We can measure performance that experts define, but we cannot measure quality, because we cannot have quality with first having the proper diagnosis. All performance measures depend on knowing the diagnosis.

But here is the key problem, defining diagnostic accuracy is extremely difficult. We often do know that we make diagnostic errors. We often do not have gold standards or reference standards for diagnosis.

Herein lies our conundrum. We want to reward quality, and thus we use proxy measures that do not actually measure quality.

We must embrace the concept of diagnostic accuracy. It is our lynchpin in all medical fields. The surgeon must make the correct diagnosis prior to cutting. The internist, the family physician, the pediatrician, the gynecologist, the ophthalmologist, the otolaryngologist, etc. all function on the basis of a diagnosis or several diagnoses. Yet current quality definitions do not take diagnostic accuracy into consideration.

Until we can better assess diagnosis, we can never assess quality. Unfortunately diagnostic errors like Thomas Eric Duncan suffered can lead to bad outcomes.