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Updated: Sep 22, 2025
Assessment of Kidney Function in Mouse Models of Glomerular Disease
Published on: June 30, 2018
Urine alpha 1-microglobulin-to-creatinine ratio and beta 2-microglobulin-to-creatinine ratio for detecting CAKUT with
Riku Hamada1, Kaori Kikunaga2,3,4, Tetsuji Kaneko5,6
1Department of Nephrology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan.
Insights
Alpha-1-microglobulin (AMCR) and beta-2-microglobulin (BMCR) ratios in urine are superior to conventional methods for detecting congenital anomalies of the kidney and urinary tract (CAKUT) in children with kidney dysfunction.
Area of Science:
- Pediatric Nephrology
- Biochemical Analysis
- Urine Biomarkers
Background:
- Congenital anomalies of the kidney and urinary tract (CAKUT) are the primary cause of advanced chronic kidney disease (CKD) in children.
- Optimal urine biochemical markers for identifying CAKUT with kidney dysfunction remain undetermined.
Purpose of the Study:
- To evaluate the efficacy of urine alpha-1-microglobulin-to-creatinine ratio (AMCR), beta-2-microglobulin-to-creatinine ratio (BMCR), protein-to-creatinine ratio (PCR), and albumin-to-creatinine ratio (ACR) in detecting CAKUT with kidney dysfunction in pediatric patients.
- To compare these markers against conventional urine dipstick analysis.
Main Methods:
- An observational study analyzed data from school urine screenings of children with CAKUT (stage 2-4 CKD) and the general pediatric population.
- Sensitivity and specificity of AMCR, BMCR, PCR, and ACR were assessed and compared to urine dipstick results.
Main Results:
- Conventional dipstick urinalysis demonstrated low sensitivity (e.g., 44.1% for stage 3 CKD).
- AMCR and BMCR showed high sensitivity and specificity for detecting CAKUT in children with stage 3-4 CKD (e.g., AMCR: 79.4% sensitivity, 97.5% specificity for stage 3 CKD).
- Findings were validated using national cohort data.
Conclusions:
- AMCR and BMCR significantly outperform dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, especially in stage 3 CKD.
- External validation for AMCR is recommended.
- These biomarkers offer a more sensitive approach to early detection of kidney abnormalities in children.
Background:
The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known.
Methods:
The present observational study analyzed data on children with CAKUT (stage 2-4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated.
Results:
In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/-, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3-4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data.
Conclusion:
AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information.
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