Calcium oxalates grown in human urine under different batch conditions

CaOx was grown simultaneously from a single pool of urine using six different protocols comparable to those found in the literature. The variations between the CaOx populations generated was great, with CaOx trihydrate detected as the most common hydromorph in two of the methods used, even though it is usually discounted in stone research. Crystal morphologies, density, particle size and surface area varied in all the methods tested, and a common technique used to remove organic matter from the crystal surface resulted in total phase transformation in one of the crystal populations. In conclusion, inter-assay comparisons of CaOx product are likely to be meaningless unless strict protocols are adhered to. Results indicate that certain crystalline properties considered relevant to stone formation may actually be a symptom of the experimental conditions.