クレアチニンクリアランス

英

creatinine clearance, C_cr

関

クレアチニン、クリアランス

クレアチニンとGFRとの解離

• 血清クレアチニンとGFRは負の相関がありかつ指数関数的な関係がある。血清クレアチニンが基準範囲よりわずかに低下するだけでもGFRは急激に低下することがある。(参考1)(参考2)

推定式

• Ccr＝((140 - age)× BW (kg))/(72×Cr(mg/dL)) (女性では×0.85)

計算

数字を入力

<raw> <FORM name="ccr"> <INPUT type="radio" name="sex" value="man" onclick="return calsex1()" />男 man <INPUT type="radio" name="sex" value="woman" onclick="return calsex2()" />女 woman
<INPUT type="hidden" name="coe" /> <INPUT type="hidden" name="coe2" /> <INPUT type="text" name="age" onkeyDown="return calccr1()" onclick="return calccr1()" onchange="return calccr1()" /> 歳 year-old <INPUT type="text" name="weight" onkeyDown="return calccr1()" onclick="return calccr1()" onchange="return calccr1()" /> kg <INPUT type="text" name="cr" onkeyDown="return calccr1()" onclick="return calccr1()" onchange="return calccr1()" /> mg/dl
Ccr = <INPUT type="text" name="calccr" disabled="disabled" /> ml/min
</raw>eGFR<raw> = <INPUT type="text" name="calgfr" disabled="disabled" /> ml/min

</FORM> <SCRIPT language="JavaScript"> function calsex1(){ ccr.coe.value = 1; ccr.coe2.value = 1; calccr1();} function calsex2(){ ccr.coe.value = 0.85; ccr.coe2.value = 0.739; calccr1(); } function calccr1(){ ccr.calccr.value = ( ( 140 - ccr.age.value ) * ccr.weight.value ) / ( 72 * ccr.cr.value ) * ccr.coe.value; calgfr1(); } function calgfr1(){ ccr.calgfr.value = 194 * Math.pow( ccr.cr.value , -1.094 ) * Math.pow( ccr.age.value , -0.287 ) * ccr.coe2.value; } </SCRIPT> </raw>

問題点

• GFRを過大評価する。体表面積で補正されていない。腎機能が安定している場合にのみ正確。

参考

• 1. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group.

• Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D.SourceNew England Medical Center, Boston, MA 02111, USA. Andrew.Levey@es.nemc.org
• Annals of internal medicine.Ann Intern Med.1999 Mar 16;130(6):461-70.
• BACKGROUND: Serum creatinine concentration is widely used as an index of renal function, but this concentration is affected by factors other than glomerular filtration rate (GFR).OBJECTIVE: To develop an equation to predict GFR from serum creatinine concentration and other factors.DESIGN: Cross-sect
• PMID 10075613

• 2.

<click2in>http://annals.org/article.aspx?articleid=712617</click2in>