Independent assessment of the growth and aggregation of calcium oxalate crystals using the Coulter counter.

The growth and aggregation of calcium oxalate seed crystals in a metastable solution of this salt were assessed separately by using the Coulter counter to measure the net increase in total crystal volume and the percentage change in total crystal number respectively. The value of assessing crystal growth and aggregation in these terms was shown by using these parameters to measure the inhibitory effect of a normal human urine. Independent assessment of growth and aggregation enabled a more accurate interpretation of experimental events than was possible by considering the two processes in combination. The method therefore has the potential of improving the discrimination between the inhibitory activities of different urines.