Values for urinary beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase in normal healthy infants.
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.
Nishida
M
M
Department of Pediatrics, Kyoto Prefectural University of Medicine, Japan. mnishida@ped.kpu-m.ac.jp
Kawakatsu
H
H
Komatsu
H
H
Ishiwari
K
K
Tamai
M
M
Tsunamoto
K
K
Kasubuchi
Y
Y
Sawada
T
T
D000118:Acetylglucosaminidase / Q000652:urine*; D003404:Creatinine / Q000652:urine; D006801:Humans; D007223:Infant; D007231:Infant, Newborn / Q000652:urine*; D012016:Reference Values; D001613:beta 2-Microglobulin / Q000652:urine*
D001613:beta 2-Microglobulin; D003404:Creatinine; D000118:Acetylglucosaminidase