Murayama test for hemoglobin S: simplification in technique.

Discussion The Ca/P ratio of the sediment is surprisingly inconsistent. The wide range makes the average (1.48) almost meaningless, although it is intriguingly close to the corresponding figure, 1.5, for synthetic tricalcium phosphate [as Cifuentes and Esteban (1) discuss]. It would be interesting to have such data to compare for urines from hyperparathyroid patients, idiopathic hypercalciurics, and patients who are chronic phosphatic stone-formers. Such information might be useful in helping to estimate the chances for stone formation. In a certain subgroup of calculous-disease patients (those who have frequent and severe incidents of crystalluria) one may conjecture that stone formation is a “statistical” process in the following sense: Every incident of crystalluria may involve a proportion of crystals large enough, or aggregated enough, to be retained in a tubule. Of these, a certain proportion is not washed out when intratubular back-pressure builds up and (or) a more dilute urine is produced. Of these “microcalculi,” a certain proportion occurs in persons whose urine composition (concentration) is such that these rudimentary stones are exposed to a milieu that facilitates their enlargement to clinically important size.