Testing for Uncommon Conditions

The improper ordering of clinical laboratory tests by physicians has generated growing concern in recent years. An estimated 5 billion tests are ordered each year in the United States, and available resources to support such widespread testing are increasingly limited.¹The growing evidence of significant geographic variations in the use of certain tests²— and that much of this testing may be unnecessary³—has stimulated national interest in the development of practice guidelines and other measures to modify physician practice behavior.⁴Much of the current concern about the magnitude of laboratory testing that has stimulated these activities has focused on its potential impact on thehealth care systemas a whole, and the principal argument has been economic.⁵Insufficient attention, however, has been given to the clinical effects of testing on thepatient, perhaps because there is a tendency to believe that such effects either