World's largest urolith database reaches two million samples

The Minnesota Urolith Center (MUC) at the University of Minnesota College of Veterinary Medicine has analysed its two millionth urinary stone. The milestone sample, an ammonium urate stone, came from Gizmo, a four-year-old Shih Tzu in New Jersey, submitted by Dr Brett Lynn and his team at MountainView Veterinary Hospital in Denville.

Founded in 1981, the centre runs the largest veterinary stone laboratory in the world and analyses close to 100,000 submissions a year free of charge for veterinary practices, using polarising light microscopy, infrared spectroscopy and X-ray crystallography. Samples have arrived from more than 50,000 clinics in 103 countries; in 2024 alone the centre examined stones from 65,000 dogs, 25,000 cats and more than 50 other species. The service is funded largely by a philanthropic educational grant from Hill's Pet Nutrition, supplemented by private donations.

The rate of submissions has picked up sharply. The first million took until 2015, the 1.5 millionth followed in 2021, and the second million five years after that.

For the industry, the value lies in the dataset behind the number. The MUC's epidemiological data on stone composition, dietary factors and metabolic drivers feeds into joint research with Hill's and underpins the therapeutic diets used to dissolve stones and reduce the risk of recurrence — a category sold largely through the veterinary channel. Beyond nutrition, the centre developed two forms of urohydropropulsion for non-invasive stone removal, identified genetic mutations behind early-onset stone formation in certain dog breeds and is now examining how the urinary microbiome influences stone formation.

Co-director Dr Eva Furrow said the milestone reflected both the number of animals affected by urinary stones and the commitment of vets, owners and the MUC team. Veterinary practices worldwide can continue to submit samples at no cost; details and submission forms are at vetmed.umn.edu/urolith-center.