To the Editor.—The report by the Maxfields1 in the April 1986 issue of the Archives on the use of colonoscopy as a primary diagnostic procedure in chronic gastrointestinal bleeding is yet another of the biased studies criticizing the barium enema that have plagued the surgical and endoscopic literature. The two most obvious faults of this investigation are as follows: (1) the use of colonoscopy as an infallible standard that inevitably determines that radiologic examination will be found inferior and (2) the absence of specific details regarding the quality of the roentgenographic examinations performed, including the thoroughness of colon cleansing. In recent radiologic reports, the sensitivity of the double-contrast barium enema has averaged approximately 90% for detection of colonic neoplasms.2 The properly performed single-contrast enema is similarly sensitive except for detection of polyps smaller than 1 cm.
Colonoscopy is not infallible. The reported false-negative error rate for polypoid