Background

Beta-2 microglobulin (β2mG) is a low-molecular-weight protein that is almost exclusively eliminated through the kidneys. It is freely filtered in the glomeruli and almost completely reabsorbed and degraded in the proximal tubules. Normal urinary β2mG levels are very low (between 0.04 and 0.22 mg/L). No reference values are known in infants and young children.

Methods

Urinary β2mG levels were measured in 103 healthy term neonates during the first week of life by nephelometric technology.

Results

The average level of urinary β2mG was 0.65 mg/L (95% confidence interval between 0 and 10.8 mg/L). There was a minor difference between male and female neonates but it did not reach statistical significance. There was no effect of the gestational week, birth weight, or weight loss in the first week of life, on urinary β2mG levels.

Conclusions

First-week urinary β2mG levels in healthy term infants were higher than adult levels. Incomplete maturation of kidney tubules in neonates could be a possible explanation. These can now be used in clinical practice and further studies that assess the degree of proximal tubular function in health and disease.

中文翻译：

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足月健康新生儿的第一周尿 β-2 微球蛋白水平

背景

Beta-2 微球蛋白 (β2mG) 是一种低分子量蛋白质，几乎完全通过肾脏排出。它在肾小球中自由过滤，在近端小管中几乎完全重吸收和降解。正常的尿 β2mG 水平非常低（介于 0.04 和 0.22 mg/L 之间）。在婴儿和幼儿中没有已知的参考值。

方法

通过比浊技术在 103 名健康足月新生儿出生后第一周测量了尿 β2mG 水平。

结果

尿 β2mG 的平均水平为 0.65 mg/L（95% 置信区间在 0 和 10.8 mg/L 之间）。男性和女性新生儿之间存在微小差异，但未达到统计学意义。孕周、出生体重或出生后第一周体重减轻对尿 β2mG 水平没有影响。

结论

健康足月婴儿的第一周尿β2mG水平高于成人水平。新生儿肾小管不完全成熟可能是一个可能的解释。这些现在可以用于临床实践和进一步研究，以评估健康和疾病中近端肾小管功能的程度。