EFFECTIVE DATE:       July 26, 2022

 

REPORTING CHANGE

 

Cystatin C, Serum

Order Code:                  CYSC

Fee Code:                     38140

 

MLabs Clinical Core Laboratory will begin providing a mathematically derived (2012 formula) estimate of glomerular filtration rate (eGFR) in adults (>or= 18 years old) when serum cystatin C is ordered. Effective July 26, 2022, eGFR Cystatin (order code GFRCY) will be automatically reported with Cystatin C requests (order code CYSC) for patients >or= 18 years of age. GFRCY is not an orderable test. There is no additional charge for this calculated value.

 

As serum cystatin C is cleared by the kidneys, serum concentrations of cystatin C may be increased in patients with kidney disease. Cystatin C-derived eGFR is NOT an appropriate test to evaluate renal function in a patient with acute kidney disease. Like creatinine-derived eGFR, cystatin C-derived eGFR is useful in some individuals in identifying chronic kidney disease. In comparison to creatinine-derived eGFR, cystatin C- derived eGFR is believed to be less influenced by high body mass index (BMI), advanced age and lean muscle mass than creatinine-derived estimates. Evaluation of any patient for kidney disease requires full consideration of the individual’s medical history as well as symptoms, signs, and other laboratory studies. Note that cystatin C-derived eGFR can be calculated only when required demographic information is available and the cystatin C concentration is within an appropriate analytical range.