Ammonium biurate crystals

Ammonium biurate

There are many brownish ammonium biurate crystals. These are yellowis-brown and have radial striations with spiky projections (so-called “thorny apple” crystals). There are moderate numbers of squamous epithelial cells in the background of this urine sediment from a male dog (these are likely from the prepuce or distal urinary tract).