Why are investigations not recommended by practice guidelines ordered at the periodic health examination?
Evidence-based guidelines recommend few routine investigations for healthy adults at the periodic health examination (PHE). However, small studies indicate that laboratory tests are commonly ordered at the PHE. This study examined PHE laboratory testing that is not recommended by recognized guidelines (‘discretionary’). Using administrative data from the universal health care system in Ontario, Canada, we studied 792,844 adults having a PHE in 1996 and the 3,727 physicians who administered them. We measured the number of discretionary laboratory tests per PHE along with the patient and physician factors potentially influencing laboratory testing. A multilevel, multivariate model was used to examine the association between the number of discretionary laboratory tests at the PHE with patient and physician characteristics. A mean of 7.1 discretionary tests (SD 7.1) was ordered per PHE. Renal, haematological, glucose and lipid tests each were conducted in more than a third of PHEs. Testing
