Availability of In-Office Laboratory Services and Use of Prostate Specific Antigen Testing

Abstract

IntroductionThere are concerns that the availability of in-office ancillary services may lower thresholds for evaluation, leading to the overuse of testing without clear benefit. Motivated by this issue, we analyzed nationally representative survey data, and examined for associations between the availability of in-office laboratory services and the use of prostate specific antigen testing. MethodsUsing restricted data from the 2006-2008 NAMCS, we determined the prevalence of physician practices offering on-site laboratory services. We then characterized differences between practices with and without these capabilities as well as among the physicians working in them. Finally, we fitted multivariable logistic regression models to estimate the odds of prostate specific antigen testing given a man’s mortality risk and the availability of in-office laboratory services at the practice where he received care. ResultsApproximately half of all primary care and urology practices offered in-office laboratory services. Practice characteristics associated with these capabilities included practice size (p <0.001) and breadth of specialization (p = 0.021). Employed physicians were more likely to work in practices with in-office laboratory services than self-employed physicians (p <0.001). On multivariable regression the availability of on-site laboratory services was not associated with the use of prostate specific antigen testing (OR 0.86, 95% CI 0.62–1.20, p = 0.362). In fact, the probability of prostate specific antigen testing among patients with the highest mortality risk was lower if they were seen at a practice with in-office laboratory services. ConclusionsThese findings provide some reassurance that in-office ancillaries do not lead to overuse of prostate specific antigen testing.