Ann Lab Med.  2013 Nov;33(6):401-405. 10.3343/alm.2013.33.6.401.

Random Urinary Calcium/Creatinine Ratio for Screening Hypercalciuria in Children with Hematuria

• Choi IS
• Jung ES
• Choi YE
• Cho YK
• Yang EM
• Kim CJ

• KMID: 1711311
• DOI: http://doi.org/10.3343/alm.2013.33.6.401

Abstract

BACKGROUND
Hypercalciuria is one of the most common causes of unexplained isolated hematuria. The diagnostic methods for hypercalciuria have not yet been standardized. The aim of this study was to assess whether random urinary calcium/creatinine ratio could be used as a screening tool for hypercalciuria in children with hematuria.
METHODS
This prospective study included 264 children with primary hematuria for whom both random and 24 hr urinary evaluations were performed. Pearson correlation and ROC curve were used to assess the correlations. A multiple linear regression model was used to analyze effects of age, weight, height, body mass index, and body surface area on random urinary calcium/creatinine ratio.
RESULTS
There was a moderately strong correlation between random urinary calcium/creatinine ratio and 24 hr urinary calcium excretion (r=0.584, P<0.001). The most appropriate cutoff value of random urinary calcium/creatinine ratio for the estimation of hypercalciuria was 0.075 mg/mg (sensitivity, 77.8%; specificity, 64.3%; area under the curve, 0.778). Body mass index and 24 hr urinary calcium excretion significantly affected random urinary calcium/creatinine ratio with a low coefficient of determination (r2=0.380, P<0.001).
CONCLUSIONS
Random urinary calcium/creatinine ratio is not suitable for screening hypercalciuria in children with hematuria. Twenty-four hour urinary analysis should be performed to diagnose hypercalciuria in children with hematuria.

Keyword

Hypercalciuria; Hematuria; Calcium; Creatinine

MeSH Terms

Adolescent
Area Under Curve
Body Mass Index
Calcium/*urine
Child
Child, Preschool
Creatinine/*urine
Female
Hematuria/*complications
Humans
Hypercalciuria/*complications/*diagnosis
Linear Models
Male
Prospective Studies
ROC Curve
Sensitivity and Specificity
Calcium
Creatinine

Figure

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  Fig. 1 Pearson correlation between random urinary calcium/creatinine ratio and 24 hr urinary calcium excretion. The Pearson coefficient (r) was 0.584 (P<0.001).

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  Fig. 2 Receiver operating characteristics curve analysis of random urinary calcium/creatinine ratio. The cut-off value (marked with a black dot on the curve) of random urinary calcium/creatinine ratio for detecting hypercalciuria was defined as 0.075 mg/mg (sensitivity, 77.8%; specificity, 64.3%; area under the curve, 0.778; P<0.001).

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