The Centers for Disease Control and Prevention found that just 21 percent of clinicians polled in a national survey routinely screen patients who have never been tested for HIV. The physicians are less likely to do so if: they have been in practice for two decades or more, when compared with those in practice for less than nine years; or if they are unaware of their patient population’s HIV infection rate or think the rate is low or moderate, when compared with those who believe the infection rate is high. Sixty-five percent of the clinicians said they routinely screen men who have sex with men (MSM), no matter the length of the physicians’ careers in medicine or their perception of their patient population’s HIV rate. Out of those who said they offer routine screening to at least one at-risk population, 85 percent reported offering repeat screenings to MSM.