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23230 Cystatin C

Cystatin C
Test Code: CYC
Synonyms/Keywords
CyC​
Useful For
Assessing kidney function for known or suspected kidney disease, but only when serum creatinine measurements are not reliable (such as obese, elderly, or malnourished patients).
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Serum​ Red Top Tube (RTT) or Serum Separator Tube (SST)​ 0.5 mL​ 0.4 mL​ 0.3 mL​
Collection Processing Instructions

​Separate serum from cells within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
Serum Refrigerate​ 7 days​
Frozen 3 months​
Rejection Criteria
​Plasma samples
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​

Monday- Friday

6-8 hours​

Analytic time may be extended if single frozen specimen is sent for multiple tests

 Turbidimetric method/The Binding Site Optilite analyzer
Test Information
Cystatin C is a low molecular weight cysteine proteinase inhibitor that is produced throughout the body and is freely filtered by glomeruli.  The serum concentration of cystatin C remains unchanged with infections, inflammatory or neoplastic states, and is not affected by body mass, diet, or drugs.  The serum concentration is inversely correlated with the glomerular filtration rate.  When using serum cystatin C to calculate GFR, the CKD-EPI cystatin equation is recommended (which is utilized by Marshfield Labs).
Reference Range Information
Performing LocationReference Range
Marshfield

Cystatin C: Adults (over age 18 years): 0.56 - 0.99 mg/L

eGFR will not be calculated for patients 18 years or under
Reference value for eGFR:  ≥ 60 mL/min

Interpretation

Cystatin C inversely correlates with the glomerular filtration rate (GFR).  Elevated levels of cystatin C indicate decreased GFR.  Cystatin C may provide more accurate assessment of GFR in patients with muscle wasting or chronic illness.

References

  1. Villa P, Jimenez M et al.: Serum cystatin C concentration as a marker of acute renal dysfunction in critically ill patients.  Critical Care 2005'9:R139-143
  2. Inker LA et al.: Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med 2012; 367:20-29
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82610​ ​ ​ ​ ​
Synonyms/Keywords
CyC​
Ordering Applications
Ordering Application Description
​Cerner ​Cystatin C
​COM ​Cystatin C
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Serum​ Red Top Tube (RTT) or Serum Separator Tube (SST)​ 0.5 mL​ 0.4 mL​ 0.3 mL​
Collection Processing

​Separate serum from cells within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
Serum Refrigerate​ 7 days​
Frozen 3 months​
Rejection Criteria
​Plasma samples
Useful For
Assessing kidney function for known or suspected kidney disease, but only when serum creatinine measurements are not reliable (such as obese, elderly, or malnourished patients).
Reference Range Information
Performing LocationReference Range
Marshfield

Cystatin C: Adults (over age 18 years): 0.56 - 0.99 mg/L

eGFR will not be calculated for patients 18 years or under
Reference value for eGFR:  ≥ 60 mL/min

Interpretation

Cystatin C inversely correlates with the glomerular filtration rate (GFR).  Elevated levels of cystatin C indicate decreased GFR.  Cystatin C may provide more accurate assessment of GFR in patients with muscle wasting or chronic illness.

References

  1. Villa P, Jimenez M et al.: Serum cystatin C concentration as a marker of acute renal dysfunction in critically ill patients.  Critical Care 2005'9:R139-143
  2. Inker LA et al.: Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med 2012; 367:20-29
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​

Monday- Friday

6-8 hours​

Analytic time may be extended if single frozen specimen is sent for multiple tests

 Turbidimetric method/The Binding Site Optilite analyzer
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
82610​ ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.