• KUB X- Ray (kidney, ureters, and bladder) X-Ray
• The colon will always contain some stool but the primary place to look for excess stool is the rectum. A normal rectum is less than 3 cm in diameter. If it is greater than 3 cm in diameter, the child is constipated
• Ask in advance for a measurement of rectal diameter.
• Ask in advance for a comment on how much poop is in the rectum.
• ADH levels and plasma osmolality (a measure of the body’s electrolyte-water balance)