Standard & Poor's bond rating service Thursday revised its financial outlook for the Detroit Medical Center (DMC) to "stable" from "positive." Analysts at one of the nation's largest rating agencies lowered the DMC's status because of concerns that patient volumes are dropping, despite the eight-hospital system's vigorous efforts to draw more business. Admissions dropped by about 850, to 79,734, from 2004 to 2005. Patient volumes also dropped in the second half of 2005 and early 2006. On the positive side, Standard & Poor's said the DMC's large patient base, relatively low debt load and a proven ability to contain costs remain strengths.