Intestinal absorption of oxalic acid in ileostomized patients.

The diagnostic usefulness of an intestinal oxalic acid absorption test was evaluated in nine patients with ileostomy. They received an oral overload of 250 mg sodium oxalate and 4 Ci oxalic acid-C14 and a controlled diet. The urinary levels of cold and radioactive oxalic acid were measured 24 and 48 hours after the overload. Intestinal oxalic acid absorption in the ileostomized patients was found to be normal, with 16.13 +/- 5.1% of the administered dose being eliminated/recovered in the urine 48 hours after the overload (control value = 14.5 +/- 2.8%). The dose of radioactivity excreted on the second day after the overload was smaller in the ileostomy group than in the control group, possibly connected with the absence of colon. The results suggest that in ileostomized patients whose colon has been removed, oxalic acid absorption is normal. Hence there appears to be no risk of oxalic lithiasis in this group.