The effect of physician personality on laboratory test ordering for hypertensive patients.

Laboratory tests are responsible for a large percentage of health care expenses in the United States. In a retrospective study of the outpatient test ordering by residents for hypertensive patients between the years 1980 and 1986 at the Department of Family Medicine at the Medical University of South Carolina, we found great variability in laboratory test ordering as well as an association between personality as measured by the Myers-Briggs Type Indicator (MBTI) and test ordering. Introverts ordered more than extroverts, and intuitives ordered more than sensors. This association was confirmed by a multiple regression analysis controlling for potential confounders of test ordering, such as severity of disease, the presence of coexisting diabetes mellitus, the demographic characteristics of the patient population, and the number of initial evaluations for hypertension. Elucidation of a relationship between resident personality and laboratory test ordering has important implications for planning intervention strategies to reduce excessive laboratory test ordering in ambulatory care.