Pet Food Recall
Laboratory Findings and Crystalluria Associated with Pet Food Recall

Background: Renal disease has been associated with consumption of various pet foods that appear to be tainted. Melamine is one nitrogen-rich compound that has been identified in many of these tainted foods. Although melamine itself may not be the toxin causing the distal tubular nephrosis observed in both cats and dogs to date, it does appear to be a good marker for the toxicity.

Crystalluria: Crystalluria has been one of the most common clinicopathologic findings associated with the recent pet food recalls. Crystals can be quite variable in size and shape. Some of the common presentations include the finding of yellow-brown crystals that are round to spherical to fan-shaped both with and without linear striations.

Note: For each image, the magnification is identified by either LPF (low power field of view; 10x objective) or HPF (high power field of view; 40x objective)

Figure 1. Urine sediment from a cat in renal failure, LPF.

Figure 2–5. Urine sediment from a cat in renal failure, HPF. Note the range in size and shape of crystals with globular to flattened crystals with slight internal linear striations. In addition, the crystals have the typical yellow-brown coloration reported in many cases to date.

Figure 6–8. Urine sediment from a cat in renal failure, HPF. Note the small size of these crystals compared to those in the previous case (Figures 2–5). The crystals have more of a consistent round to spherical shape with delicate internal linear striations. In addition, as with the other crystals, there is a pale yellow-brown coloration to the crystals.

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