Cystatin C Creatinine EGFR panel

CYSTATIN C CREAT EGFR PANEL(WH)

Creatinine
Cystatin C
EGFR(Creatinine-Cystatin C)
 

serum, separated from cells

refrigerated

Separated serum is stable for 14 days at room temp or 21 days refrigerated

Test	Reference range
Cystatin C	0.51 - 1.05 mg/L
Creatinine	0.5 - 1.5 mg/dL
EGFR(Creat-Cystatin c)	60 mL/min

Cystatin C may provide a better estimate of glomerular filtration rate (eGFR) compared to creatinine in Veterans with extremes of muscle mass (e.g., elderly, Veterans with spinal cord injury or significant limb amputation, body builders), weight, or diet (e.g., high in red meat, fish, supplemental creatine) [1]. Cystatin C based eGFR is also recommended as a confirmatory test when there is uncertainty about diagnosis of CKD (e.g., new finding of persistent creatinine based eGFR < 60 cc/min). Unlike creatinine, a breakdown product of creatine phosphate in skeletal muscle, cystatin C is produced by all nucleated cells. The combination of cystatin C and creatinine may also provide added value in patients with higher GFR, as the eGFR estimate with creatinine (2021 CKD-EPI) has higher bias [2].
 
The best estimate of eGFR is obtained from the combination of cystatin C and creatinine [2]. Therefore, Cystatin C will be available only as a panel with serum creatinine and the calculated eGFR (CYSTATIN C CREAT EGFR PANEL(WH)). Estimates of eGFR with cystatin C and creatinine are not race-based (2021 CKD-EPI). Online calculators are available for interested clinicians to explore further [3].

 
[1] https://www.kidney.org/atoz/content/cystatinC
[2] https://www.nejm.org/doi/full/10.1056/NEJMoa2102953
[3] https://www.kidney.org/content/ckd-epi-creatinine-cystatin-equation-2012