Radiographic contrast media may cause a number of changes in the urine. Having a history of recent imaging studies with contrast makes the diagnosis a lot easier.
Changes associated with radiographic contrast media:
(1) cloudy urine with visible precipitate
(2) crystals at an acid pH that are strongly birefringent (see below)
(3) high specific gravity (> 1.035) by refractometer if a high osmolar agent was used
(4) discrepancy in specific gravity readings between reagent strip and refractometer
(5) false positive urine protein test by the sulfosalicylic acid precipitation test
