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• Overuse of diagnostic testing: possible explanations and solutions
  Steven H. Horowitz
  Published on: 16 December 2021

• Published on: 16 December 2021

  Overuse of diagnostic testing: possible explanations and solutions

  • Steven H. Horowitz, Neurologist Tufts University School of Medicine

  The recent article by Muskens et al "Overuse of diagnostic testing in healthcare: a systematic review" published online on May 10, 2021, admirably describes the prevalence and overuse of low-value diagnostic tests in multiple healthcare settings, but does not offer possible explanations or solutions. Some salient reasons are (1): 1. Physicians do not consider healthcare costs during a diagnostic workup; 2. Malpractice concerns; 3. An excessive fee-for-service mentality--more tests and consultations generate more income; 4. Lack of trust in clinical skills versus high technology testing; 5. Believing that diagnostic workups should eliminate all conceivable etiologies; and 6. Patients may experience greater satisfaction with more testing.

  Underlying these last three possibilities is the failure to appreciate that in science, especially after Darwin, Einstein and Heisenberg, absolute certainty is considered unachievable. Facts and theories, and clinical diagnoses, are now rated on the probability that they are true. A diagnosis is more probable than not, or more probable than another, based on degrees of evidence. Hence recent interest in Bayesianism, which analyses evidence in terms of probability. When determining the efficacy of additional tests, Bayesianism requires a pre-test (a priori) probability estimate of the diagnosis. The more probable a diagnosis is clinically (a priori) and the greater the diagnostician's clinical confidence, the less nec...

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  The recent article by Muskens et al "Overuse of diagnostic testing in healthcare: a systematic review" published online on May 10, 2021, admirably describes the prevalence and overuse of low-value diagnostic tests in multiple healthcare settings, but does not offer possible explanations or solutions. Some salient reasons are (1): 1. Physicians do not consider healthcare costs during a diagnostic workup; 2. Malpractice concerns; 3. An excessive fee-for-service mentality--more tests and consultations generate more income; 4. Lack of trust in clinical skills versus high technology testing; 5. Believing that diagnostic workups should eliminate all conceivable etiologies; and 6. Patients may experience greater satisfaction with more testing.

  Underlying these last three possibilities is the failure to appreciate that in science, especially after Darwin, Einstein and Heisenberg, absolute certainty is considered unachievable. Facts and theories, and clinical diagnoses, are now rated on the probability that they are true. A diagnosis is more probable than not, or more probable than another, based on degrees of evidence. Hence recent interest in Bayesianism, which analyses evidence in terms of probability. When determining the efficacy of additional tests, Bayesianism requires a pre-test (a priori) probability estimate of the diagnosis. The more probable a diagnosis is clinically (a priori) and the greater the diagnostician's clinical confidence, the less necessary is additional testing. Since it is impossible to prove absence of disease, testing can only support or not support a specific clinical diagnosis.

  But there is a quid pro quo: Tests can be harmful and costs uncontrolled. Given the subjective nature of characterizing truth and justifying beliefs, the medical profession might consider differentiating levels of evidence or burdens of proof regarding diagnostic accuracy much as the legal profession does: in less stringent civil cases the burden of proof is preponderant, more likely than not, >50%. In more severe criminal cases the burden of proof is beyond reasonable doubt, indubitable. While this legal dichotomization is probably too simplistic for all clinical issues, it can serve as a guide. Graded burdens of proof for differing clinical presentations could alter physician behavior, enhance patient satisfaction, reduce malpractice concerns, and contribute to lower health care costs without compromising individual patient care.

  Parenthetically, after decades of teaching medical students and house staff officers of the importance of clinical skills to minimize excessive testing, I joined a multispecialty healthcare group from which I was eventually dismissed for not ordering enough tests and generating sufficient testing income. My philosophy, which I strongly believe in, came back to bite me.

  1. Horowitz SH. Diagnostic decision-making, burdens of proof, and a $6000 per hour memory lapse. JAMA Int Med; 2013;176:1493-1494.

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  Conflict of Interest:
  None declared.

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