Diagnostic Certainty: Can We Ever Get It Just Right?
How confusing is this? You speak to one attending who tells you that you should come down hard on a diagnosis in your impression. No differential, please. (usually a more senior attending) And, then, the next one tells you to make sure to put all the diagnostic possibilities in your dictation with impunity. (most likely the attending that has been sued several times!) Well, if you are a resident, this situation most likely applies to you. Why? Because every attending sets their threshold for certainty. And, each does it based on their experience and insight. So, where do you set your limits for diagnostic confidence as a radiology resident?
How I Developed My Level Of Certainty (A Bit Of Back And Forth)
In my residency program, the faculty and program director emphasized saying what you mean and meaning what you say. If a study appeared normal, call it normal. Or, if you had a patient with all the findings of an adrenal adenoma, call it such. End of story.
But, as I went along in my training, I began to realize that most normals are not exactly “normal.” And, even the most “certain” diagnoses are not indeed “certain.” Now, in these situations, you will be right 99.9% of the time. However, in that 0.1%, you will discover something different. In essence, by following the philosophy of my residency program, I resigned myself to automatically missing some of those rare zebras. These two discrepant themes played itself over and over, conflicting with my initial training.
So, how did I resolve this conflict? First, I recognized that I would have to be wrong a tiny but real percentage of the time to make the right recommendation for the referring physician. Moreover, I realized if I left some of those rare birds in the dictation, I would lead my referrers astray in most situations. In essence, I would increase costs to the patients and the health care system as a whole. So, calling something normal when you think it is normal did begin to make some sense again. I began to approach my dications from that angle.
But wait, what happened if that Haversian canal was that fracture that you thought unlikely since there was no adjacent soft tissue swelling? Or, what transpired when that stoolball stuck in the middle of the colon turned out to be a massive polyp? Was I setting myself up for massive lawsuits? Herein lies the rub. Over time, I realized I could not be too sure in any report.
How I Resolved (Some) Of The Certainty Conflict
I’d love to say that you can conquer this fight between certainty and uncertainty in one fell swoop. But, to say so would be naive and even worse, outright dangerous. All I could do is to mitigate the potential pitfalls. It has been a slow process to figure it all out.
So, how did I begin to tamp down this conflict to a much lower level? Well, it’s all about probability. I made sure to give a measured response in my dictations about the likelihood of my primary diagnosis versus the most reasonable zebras. That worked 99 percent of the time. It reduced the probability of zebra misses. Likewise, most physicians will use your primary diagnosis and follow the recommendations.
Why Giving Probablilities Does Not Always Work
Here’s the real issue, however. Your audience could be a physician assistant, a nurse practitioner, or a physician. Some may have more or less experience. And, this provider may practice patient care based on your unlikely diagnosis of a zebra instead of the more probable outcome. So, no matter how hard I try to steer the referrer in my preferred direction, that clinician may not use the probabilities in any report as I have intended. We must accept this fact. And, that is a tough pill to swallow.
Feeling Comfortable With Your Level Of Certainty
But, knowing that we cannot control for rogue clinicians, we can only do our best to relay our probabilistic approach without making the misses that can endanger our livelihood. It’s a sacrifice we must make to practice our specialty. And, we should do it in a manner that will lead the majority of clinicians to the most appropriate patient care as well as mitigate the potential for lawsuits. Remember. We are not here to control the flow of patient care in every patient, but rather to guide it. I can take some comfort in that notion!