But My White Count…

Excerpt – Consulting medical teams nearly always follow my antibiotic recommendations, no matter how idiosyncratic they may seem, but recommending that they stop checking white-cell counts on stable inpatients seems to strike them as beyond the pale.

Much of this trend is driven, I believe, by the quantitative fallacy: the human tendency to attach too much weight to factors that are easy to measure, and not enough weight to more complex, hard-to-quantify variables. This inclination induces doctors and patients alike to obsess over the crisp, objective, but highly nonspecific assessment of leukocytosis, while eschewing the seemingly squishy but highly informative subjective impression of severity of illness as felt or seen by the patient, their family, and the treating clinical teams.

A related issue arises from conflating the assessment of an acute infection with the diagnosis of other chronic medical conditions. Patients cannot in general feel the ups and downs of their blood pressure, glucose level, or serum cholesterol concentration, so we rely on laboratory testing to guide management. For acute infection, though, it is seldom mysterious whether or not a patient is ill. As social animals, we have been endowed by natural selection with very sensitive illness and recovery detectors for ourselves and our fellow humans. During medical training and practice, these wired-in instincts become honed to an exquisite degree. Laboratory testing may refine the specifics of a diagnosis, but they are typically not needed to know whether a patient’s condition is improving with antibiotics.

[..] just as the practice of antimicrobial stewardship informs antibiotic use, so do the related principles of diagnostic stewardship3 help regulate the data firehose that is modern medicine. Ordering and analyzing only those tests deemed most likely to improve patient outcomes can help us avoid excessive antibiotic use, imaging, and delays in discharging patients. It can also free up more of the most critical limiting resource — our attention — for the data that are actually most useful to our patients.

[..] Squishy and nonquantitative though it may be, when trying to suss out the day-to-day diagnostic subtleties of acute infection, I still find the most informative initial probe to be the simple query: “So, how are you feeling?”

Full commentary, R Colgrove, New England Journal of Medicine, 2024.2.14