Oxalate and struvite stones: Urinalysis in cats | Vets &Clinics

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Oxalate and struvite stones: Urinalysis in cats

Oxalate and struvite crystals are one of the main causes of feline lower urinary tract disease (FLUTD). Although the leading cause is feline idiopathic cystitis, urinary crystals occupy second place and are responsible for 25% of cases. An early diagnosis by means of a urinalysis is important to institute the most suitable treatment as soon as possible and therefore reduce the recurrence rate.

Veterinary medicine and care

Calcium oxalate and struvite crystal formation

There are severl factors contributing to the formation of the different types of urinary crystal. The most common ones are struvite (60%), then calcium oxalate (30%) crystals1. This problem is affected by the drinking water’s degree of mineralisation  and which modifications in a cat’s diet can reduce the incidence of urinary crystals.

Urinalysis: a method of early diagnosis

Urinalyses are used to evaluate the physicochemical characteristics of urine. The test results provide an indication of the urine solute concentration. A microscope examination of urine sediment is also carried out to determine the presence of cells, casts or calcium oxalate and struvite crystals.

It is mainly indicated for the suspicion of urinary system diseases, but it also provides information about the rest of the cat’s organism.

The main parameters evaluated are:

  • Volume
  • Colour
  • Specific gravity
  • Turbidity
  • pH
  • Cells: red blood cells, leukocytes, bacteria, epithelial cells
  • Biochemical parameters

Disease associated with the presence of urinary crystals

It is very important to test for the presence of urinary crystals, both oxalate and struvite, especially in cats with urinary problems, as FLUTD has a very high recurrence rate. In a large number of cases FLUTD is not due to an infection, but rather only to the presence of these crystals.

The cat’s diet can be adjusted to eliminate the problem and prevent the recurrence of FLUTD. The Affinity Petcare R&D team conducted research into FLUTD and its relationship with calcium oxalate and struvite crystals in order to learn how to treat FLUTD by modifying the animal’s diet. Struvite stones are very important in FLUTD. 

If you want to learn more about water mineral levels and increasing watering points to reduce FLUTD in cats, we recommend downloading the clinical report available below in PDF:

In brief, apart from urinalysis there are other laboratory tests that require proper sample handling and correct interpretation. We would now like to take the opportunity to introduce you to the Pocket VETLAB , a guide prepared by vets and for vets. It is a constantly updated, pocket-sized guide to veterinary laboratory analysis in small animals. It features dynamic protocols to help veterinary surgeons make quick, accurate diagnoses.

  • RR Feline lower urinary tract disease (FLUTD) and its dietary management [La enfermedad de las vías urinarias (FLUTD) y su tratamiento dietético] Isabelle Jeusette
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