title: Spurious rise in total carbon dioxide and chloride with negative anion gap after cystogram.
abstract: We report a case of spurious hyperchloraemia, elevated total carbon dioxide and negative anion gap 9 days following a voiding cystourethrogram (VCU) in a patient with bladder exstrophy and obstructive uropathy. We believe that the spurious laboratory results were due to analytical interference of the absorbed iodine with the method of bicarbonate and chloride measurement. The absorbed iodine was retained in the circulation for an extended period because of associated renal impairment. Our patient was also on piperacillin which might have interfered with iodine clearance. Physicians and laboratory pathologists should be aware of this effect when interpreting laboratory results of patients who have undergone a VCU in association with obstructive uropathy and impaired renal function.
authors.affiliation: Department of Pathology, University of British Columbia, Vancouver, Canada.
authors.forename: L O
authors.initials: LO
authors.lastname: Abdel-Wareth
authors.forename: D S
authors.initials: DS
authors.lastname: Lirenman
authors.forename: A C
authors.initials: AC
authors.lastname: Halstead
authors.forename: D
authors.initials: D
authors.lastname: McLellan
authors.forename: B C
authors.initials: BC
authors.lastname: Carleton
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D003287:Contrast Media / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D008297:Male; D014525:Urethral Stricture / Q000000981:diagnostic imaging; D014567:Urography / Q000009:adverse effects*
chemical_list: D002712:Chlorides; D003287:Contrast Media; D007457:Iodine Radioisotopes; D002245:Carbon Dioxide