Cystatin C
Test Mnemonic
CYSTC
CPT Codes
- 82610 - QTY (1)
LOINC ®
87430-5
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Plasma | Lithium heparin PST (Lt. Green) | Refrigerated | Centrifuge and refrigerate. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Serum | SST (Gold) | Refrigerated | Centrifuge and refrigerate. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.4 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | After separation from cells: 7 days |
| Refrigerated | After separation from cells: 7 days |
| Frozen | After separation from cells: 6 months |
Days Performed
Mon - Sun
Turnaround Time
24 hours
Methodology
| Name | Description |
|---|---|
| Quantitative Immunoturbidimetric |
Special Info
Clinical Info
Evaluation of renal function. eGFR Calculation: Adults: 2012 CKD-EPI cystatin C equation Pediatric (2-17 yrs): 2012 Schwartz cystatin C equation Cystatin C is produced by all nucleated cells at a constant rate and the production rate in humans is remarkably constant over the entire lifetime. Elimination from the circulation is almost entirely via glomerular filtration. Cystatin C based eGFR calculation may be clinically useful in certain scenarios where creatinine-based eGFR may be misleading (e.g. muscle wasting).
Clinical Limitation
Cystatin C levels are sensitive to changes in thyroid function and should not be used without knowledge of the patient's thyroid status.