eGFR


Abbrev Code:CREA   
Order Code:LAB66Order Name:GFR Estimated
Synonyms:Estimated Glomerular Filtration Rate, Calculation
Methodology:Calculation using 2021 CKD-EPI creatinine equation on every serum creatinine with the following exceptions: patient is <18 years, sex unknown, or creatinine is <0.05 mg/dL.
CPT Codes: 82565 x1


Collection Instructions

Specimen:Calculation performed with Serum/Plasma Creatinine.


Processing and Shipping

Test Performed at or Referral Lab Chemistry  (CSC Maple Grove, Grand Itasca, Northland, Oxboro Clinic, Range, Roche-CSC Mpls, Roche-Lakes, Roche-Ridges, Roche-St. John's, Roche-UMMC East, Southdale, UMMC/UMMCH-West Bank, Woodwinds)


Interpretive

Reference Range:

>60 mL/min/1.73m2. 90 mL/min/1.73m2 or higher indicates normal renal function. Values less than 90 mL/min/1.73m2 may indicate impaired renal function. However, all values should be interpreted with respect to the patient's clinical status and age and urine albumin-creatinine ratio (uACR). eGFR declines with age in healthy people.

 

 

Limitations:Situations in which non-GFR factors may have had a large effect on serum creatinine include alterations in creatinine generation (muscle wasting diseases, amputees, body builders, vegan diet) drugs that affect tubular secretion of creatinine (cimetidine, cobicistat, dolutegravir, fenofibrate, ritonovir, trimethoprim and others) and conditions with extra-renal elimination of creatinine (gastrointestinal and "third-space" losses).

2021 recommendations from the CKD-EPI committee: eGFRcr values need to be interpreted based on clinical context. Clinical practice recommendations suggest ordering cystatin C as a confirmatory test for patients with eGFRcr of 45-59 mL/min/1.73m2 with uACR <30 mg/g, and in patients for whom the creatinine may be a less reliable indicator of GFR near decision points. eGFRcr-cys provides a more accurate estimate of GFR. In addition, eGFRcys may be more accurate in conditions when creatinine is a less reliable test for estimating the GFR.
Use:Effective December 21, 2021, M Health Fairview Laboratories changed the calculation of estimated glomerular filtration rate (eGFR) to the new 2021 CKD-EPI creatinine equation that does not include a race coefficient. The new eGFR equation has similar overall performance characteristics to the older equations and has been validated to not disproportionately affect any one group of individuals. For most patients, the eGFR result will be similar, however, for some, the values may differ by more than 10% particularly at higher values of eGFR and for younger adult ages.  

2021 CKD EPI Qualifiers and Equations
Female (Scr ≤0.7) eGFRcr = 143 (Scr/0.7)-0.241 x 0.9938Age
Female (Scr >0.7) eGFRcr = 143 (Scr/0.7)-1.200 x 0.9938Age
Male (Scr ≤0.9) eGFRcr = 142 (Scr/0.9)-0.302 x 0.9938Age
Male (Scr >0.9) eGFRcr = 142 (Scr/0.9)-1.200 x 0.9938Age
Note: Scr = Serum Creatinine
The new calculation/calculator can be found here: https://www.kidney.org/professionals/kdoqi/gfr_calculator
 
2021 CKD-EPI Recommendations:
  1. Immediate implementation by all U.S. laboratories of the CKD-EPI creatinine equation refit without the race variable.
  2. Recommendation for national efforts to increase the routine and timely use of cystatin C, especially to confirm eGFR in adults for clinical decision making.
  3. Recommendation to encourage research on GFR estimation with new endogenous filtration markers (e.g., creatinine and cystatin C) and interventions to eliminate racial and ethnic disparities.


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