All of the following statements regarding hirschsprung disease are TRUE, EXCEPT:

Diagnosis Of Hirschsprung's Disease Rectal manometry and rectal suction biopsy are the easiest and most reliable indicators of HD. Rectal suction biopsies are the procedure of choice and should be performed no closer than 2 cm to the dentate line to avoid the normal area of hypoganglionosis at the anal verge. Anorectal manometry measure the pressure of the internal anal sphincter while a balloon is distended in the rectum. In patient with HD, pressure fails to drop or there is a paradoxical rise in pressure with rectal distension. Barium enema examination should be done in unprepared bowel as washout may minimise the dilation of the gut above the obstruction. It is always essential that both AP and lateral view should be taken as narrow sho segment may be overlapped by dilated proximal colon in one of the view's. Ref: Love & bailey 25/e, page 86-87 ; Nelson 18/e, page 1565-67 ; S. Dass Textbook of Surgery 5/e, page 1035-36