1) after surgery to place a new colostomy, it normally takes an avg. of 3 to 6 days for the colostomy to begin functioning. 2) you need a urine sample to complete a Schilling test( used to assess absorption of b12 in GI tract. 3) calcium is the antidote for serum magnesium sulfate excess.. 4) bright orange urine is a common side effect of Pyridium. 5) while a pt is on heparin therapy the most important lab test to check regularly is partial thromboblastin time(ptt)