Studies of urease-induced crystallisation in undiluted human urine using the Coulter counter technique.

Urease-induced crystallisation was studied in different human urine samples after urease incubation. The studies were performed using the Coulter counter technique, which enables determination of the number and size of particles in a solution and calculation of the total particle volume. The crystallization took place in three consecutive but overlapping steps: (1) nucleation, (2) growth and (3) aggregation. The maximal number of particles obtained in the different samples varied little, but there was a great variation in particle size and total particle volume. The variation in particle size appeared to be mainly due to differences in particle growth, a factor that might be of importance for stone formation.