クレアチニンとシスタチンCによる小児の年齢と腎機能評価

Age effects on reference serum creatinine and serum cystatin C levels in Japanese children

血清クレアチニン(s-Cr)の基準値は，2008～2009年に日本小児腎臓病学会の小児慢性腎臓病(CKD)対策委員会で検討された．s-Crと身長との間の相関は，2～11歳の小児で検討し，回帰式は，“推算されるs-Crの基準値＝身長(m)×0.30”となった．筆者らは，さらに全年齢において身長とs-Crの関係を示す多項回帰式を男児と女児に分けて作成した．血清シスタチンC(CysC)の基準値については，生後1歳までに段階的に低下し，その後ほぼ一定になった．しかし，1歳児と2歳児でもわずかに異なった．s-CrやCysCの基準値を利用して，小児CKD患者のステージ分類を診断する方法について提案した．

The reference values of serum creatinine (s-Cr) and cystatin C (CysC) were determined by the Committee of Measures for Pediatric CKD between 2008 and 2009.　The correlations between s-Cr and body length were evaluated in subjects aged 2～11 years.　The regression equation that passed through the origin was estimated as reference s-Cr＝body length(m)×0.30.　We also determined the relationships between body length and s-Cr by polynomial regression analysis in males and females separately.　We found that reference serum CysC concentration gradually decreased during the first year after birth, thereafter becoming constant.　Mean serum CysC concentration was slightly higher in children aged 1 year than in children aged ≥2 years.　We would like to show methods to diagnose the stages of pediatric CKD patients using reference values of s-Cr.