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Updated: Jul 20, 2026

Biochemical Measurement of Neonatal Hypoxia
Published on: August 24, 2011
Values for urinary beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase in normal healthy infants
M Nishida1, H Kawakatsu, H Komatsu
1Department of Pediatrics, Kyoto Prefectural University of Medicine, Japan. mnishida@ped.kpu-m.ac.jp
Background:
Measuring urinary beta 2 microglobin (B2M) and N-acetyl-beta-D-glucosaminidase (NAG) excretion is widely used as a valuable clinical tool in assessing renal tubular lesions. However, few data are available on normal values for urinary excretion of B2M and NAG in infancy.
Methods:
Urinary B2M and NAG were measured in healthy infants. The logarithmic values of urinary B2M, NAG, B2M/creatinine ratio and NAG/creatinine ratio were distributed almost normally and reference ranges were calculated from the logarithms of the observed values.
Results:
The levels of urinary B2M and B2M/creatinine ratio were highest in the 1-month-old group, followed by a decrease during the first 3 months. Urinary B2M excretions in the 3-month-old group showed rather lower levels than those of the 12-month-old and 36-month-old groups. Although urinary NAG excretions were almost constant throughout all groups, urinary NAG/creatinine ratio decreased gradually until 3 years of age.
Conclusions:
We suggest that these reference ranges are of importance in evaluating tubular damage due to a variety of renal diseases in infancy.
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