| Objective To explore the method of using the product of fasting 1-hour urinary calcium concentration (1h UCa) and 24-hour urine output to replace 24 HUC, to find the best cut-off, and to judge the agreement. Methods 24-hour urine samples were collected. The 24-hour average urine calcium concentration, 1hUCa and 24-hour urine output were measured. The correlation between 24-hour average urine calcium concentration and 1h UCa was analyzed. The correlation between product of 1h UCa and 24 HUC was analyzed. ROC curve was drawn to find the cut-off point. The sensitivity, specificity, and misdiagnosis rate were evaluated. The agreement between there was judged with Bland–Altman analysis. Results The product of 1h UCa and 24-hour urine output was significantly correlated with 24 HUC. When 24 HUC>350mg/d was chosen as the cut-off point to draw ROC curve for the diagnosis of hypercalciuria, the area under the curve was 0.993. When 10.969 mmol/d was chosen, the sensitivity, specificity, and misdiagnosis rate were 100%, 96%, and 20%, respectively. The diagnosis indicator was 2.545 higher in average than 24hUC, with 95% agreement interval of -6.4 to 2.7. Conclusion Because of the good sensitivity, specificity, low misdiagnosis rate, and the good agreement, the product of 1h UCa and 24-hour urine output can replace 24 HUC to diagnose hypercalciuria. |