Adult: 0.5–1 mg/L
Child: 0–3 mo: 0.8–2.3 mg/L; 4–11 mo: 0.7–1.5 mg/L;
1–17 yr: 0.5–1.3 mg/L
. Red-top tube.
■ A cysteine protease inhibitor that is freely filtered
(removed) by the glomeruli and thus can be used to assess
for changes in glomerular filtration rate.
■ High levels of cystatin C suggest impaired renal function.
■ It is thought to be superior to creatinine as a marker of
glomerular filtration rate because it is not affected by
muscle mass, diet, or acute inflammatory processes.
