[Oral purine loading in the routine diagnosis of patients with urinary calculi]

Oral purine loading: a diagnostic procedure in stone forming patients. 95 stone formers (83 patients with calcium oxalate and calcium phosphate, 12 patients with uric acid stones) and 10 healthy volunteers were given 2 g guanosine as an oral purine load. Calcium oxalate and caldium phosphate stone formers showed two different patterns of uric acid excretion after oral purine loading, correlating with different incidence of recurrent stone formation. Patients with uric acid lithiasis showed initially lower values of urate excretion, after oral purine load no difference of uric acid excretion compared to normal controls was seen.