The Limits of Medical Testing:
Guillain-Barré was a diagnosis that had been considered by the team, but which had been set aside when the spinal tap was normal. An elevated protein level in the spinal fluid is seen in 90 percent of cases after one week. This test was done just a couple of days after the patient became ill. Had it been done a few days later, it might have been positive.
No test is perfect; they all have limitations. And yet when we get a result, our temptation is to believe it and use that result to either diagnose or rule out a disease process. In medicine, there is often tremendous tension between the urgent need for diagnosis and treatment of a seriously ill patient and the uncertainty of the data we have available to help us make that diagnosis and choose that treatment.
The patient — sick, tired and often distracted by her illness — must provide the basic who-what-and-where of the disease. The physical exam, an indirect assessment of the problems inside the body from inspecting, percussing and palpating the outside of the body, is often uninformative. Those tests doctors and patients alike turn to for certainty have their own rate of error and built-in limitations. And often, data must be obtained and interpreted under the most literal of deadlines.As I practice longer, I realize that uncertainty dominates certainty in the practice of medicine. How is the concept of uncertainty integrated into the training of the next generation of physicians?
It’s a messy process, filled with red herrings and dead ends, and yet it’s all we’ve got — at least for now.
I am engaged in the training of medical students and residents, but I am not particularly engaged in formal classroom teaching. However, do I give a few formal lectures each year to the medical students and I have done so for years. Only recently has the lecture evaluation process been robust. I like the idea of feedback but I have to admit that I have been somewhat taken aback by some of the critiques and have found at least some of the comments rather strange. After my initial annoyance, I realize that it is important to step back from my immediate response to criticism and think about the mindset of those who are listening to the lectures.
One particular comment, stating their desire for me to include fewer references to original basic scientific studies (e.g - PCR references) and just tell them what they need, was especially enlightening. I had to ask ... What are their needs? Do I know their needs or do they know their needs? Do they need to understand where the information which we base our clinical judgment comes from and learn to place data they garner in context?
The reality is the only thing they know for certain are their immediate needs and their immediate needs do not include learning things which will ultimately benefit the patients which they ultimately chose to care for. Their immediate need is to get good grades on the test. They want the facts and only the facts which they will be tested on. Their tests are filled with questions which have "right" answers, something which is actually a rarity within clinical medicine. We train students in an artificial world with right answers for a world filled with uncertainty and ambiguity.
These are smart young men and women who are very focused on the task at hand, that is to get good grades and do well on standardized tests in order to match in highly competitive residencies. Appreciation of uncertainty and ambiguities is the road to becoming unfocused.
Medical educators have created a trap for themselves and their students. Using the classic information acquisition and testing model, success can only be assessed by measuring how many testable morsels can regurgitated. Many if not most of these morsels are either wholly irrelevant or simply untrue (although widely embraced). The right/wrong format embraced by the testing culture reinforces the obliviousness to ambiguity and uncertainty which then serves as a barrier to the development of real judgement and wisdom in the practice of health care. The appreciation of subtlety is not something cultivated by multiple choice exams.