高尿钙诊断方法探索

The investigation of diagnostic method of hypercalciuria

目的寻找替代24hUC诊断高尿钙的指标,尝试利用空腹1小时尿钙浓度(fasting 1-hour urinary calcium concentration,1hUCa)与24小时尿量的乘积诊断高尿钙,探索其最佳诊断切点,并判断与24hUC相比,两种方法的一致性。方法留取24小时尿及随后的空腹1小时尿标本,分别测定24小时平均尿钙浓度、清晨空腹1小时尿钙浓度,计量24小时尿量,计算24小时尿钙,行24小时平均尿钙浓度与1hUCa的相关性分析,以空腹1小时尿钙浓度与24小时尿量的乘积为诊断指标,行该值与24hUC的相关性分析,做ROC曲线寻找最佳诊断切点,并计算其敏感度、特异性、误诊率,采用Bland-Altman绘图和数据分析,比较该诊断指标与24HUC的一致性。结果清晨空腹1小时尿钙浓度*24小时尿量的乘积与24小时尿钙具有显著的相关性,以其诊断高尿钙时,将24HUC>350 mg/d选取为诊断切点,所做ROC曲线,曲线下面积为0.993。其值选取10.969 mmol/d为切点时,敏感度为100%,特异性为96%,误诊率20%。该诊断指标平均高于24HUC 2.545,95%一致性界限在-6.4和2.7之间。结论由于敏感度和特异性好,误诊率低,一致性好,空腹1小时尿钙浓度与24小时尿量的乘积能代替24hUC作为高尿钙诊断指标。

Objective To explore the method of using the product of fasting 1-hour urinary calcium concentration（1 hUCa） and24-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,1 hUCa and 24-hour urine output were measured.The correlation between 24-hour average urine calcium concentration and 1 hUCa was analyzed.The correlation between product of 1 hUCa and24-hour urine output 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 them was judged with Bland-Altman analysis.Results The product of1 hUCa and 24-hour urine output was significantly correlated with 24 HUC.When 24 HUC 〉350 mg/d was chosen as the cut-off point to drawROC 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 was2.545 higher in average than 24 hUC,with 95% agreement interval of-6.4 to 2.7.Conclusion Because of the good sensitivity,specificity,lowmisdiagnosis rate,and the good agreement,the product of 1 hUCa and 24-hour urine output can replace 24 HUC to diagnose hypercalciuria.