ppears to be of fundamental importance to get information
on the inhibiting properties of the urine. Several methods have
been described for doing so. Some techniques are designed to
measure the inhibition in untreated urine samples (11, 15),
in which the result is a combined effect of the supersaturation
of the urine and the inhibiting activity. For the study of only
the effects of crystallization inhibitors, systems involving
diluted urine have been described, the dilutions usually used
being 20-fold or greater. In the method described by Robertson et a!. (6) crystal growth and aggregation were measured
simultaneously, whereas other methods (7, 9, 14, 16) were
developed for determining only crystal growth rate. Most of
these methods are complicated and time consuming and often
require expensive special equipment, which considerably
limits their usefulness in the routine clinical laboratory.