Bilirubin crystals tend to precipitate onto other formed
elements in the urine. In the top picture, fine needle-like
crystals have formed on an underlying cell. This is the
most common appearance of bilirubin crystals. In the
lower two pictures, cylindrical bilirubin crystals have
formed in association with droplets of fat, resulting
in a "flashlight" appearance. This form is less commonly
seen.
Bilirubin crystals are seen most commonly in canine urine, especially in highly concentrated specimens. They are less common in urine of other species. In dogs, they often are of no significance (healthy dogs can have low, but detectable, bilirubin levels in urine). Bilirubin crystals (or a positive chemical reaction on the urine dipstick) in feline, equine, or bovine urine should be investigated since an underlying cholestatic process is likely. |
Last Updated: January 15, 1996