MediCalc

Indicator Description

eGFR (estimated renal filtration rate) is a vital indicator for assessing kidney function. This calculator uses the MDRD formula to calculate eGFR values based on age, gender, serum creatinine, and race.

eGFR values' clinical interpretation:

• ≥90 mL/min/1.73m²: Normal or mild reduction (CKD 1 stage, if renal injury evidence)
• 60-89 mL/min/1.73m²: Mild to moderate reduction (CKD 2 stage, if renal injury evidence)
• 30-59 mL/min/1.73m²: Moderate to severe reduction (CKD 3 stage)
• 15-29 mL/min/1.73m²: Severe reduction (CKD 4 stage)
• <15 mL/min/1.73m²: Renal failure (CKD 5 stage)

Calculation Formula

1. CKD-EPI formula (2021) - Basic version

CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 formula is currently the international recommendation for eGFR calculation formula, aimed at enhancing accuracy and eliminating race coefficient. Basic version only requires age, gender and serum creatinine.

Formula:

Parameter Description:

1) Female

C value: 1.012

Scr≤0.7mg/dL	Scr>0.7mg/dL
k = 0.7 α = -0.241	k = 0.7 α = -1.2

2) Male

C value: 1

Scr≤0.9mg/dL	Scr>0.9mg/dL
k = 0.9 α = -0.302	k = 0.9 α = -1.2

2. CKD-EPI formula (2012) - Creatinine-cyst C combined version

This version combines serum creatinine and cyst C two biochemical markers, intended to provide more accurate eGFR estimation, especially eGFR is within 60-90 mL/min/1.73m² range.

Formula:

Parameter Description:

1) Female

C value: 0.963

	Scr≤0.7mg/dL	Scr>0.7mg/dL
Scys<=0.8mg/L	k = 0.7 α = -0.248 e = 0.8 f = -0.375	k = 0.7 α = -0.601 e = 0.8 f = -0.375
Scys>0.8mg/L	k = 0.7 α = -0.248 e = 0.8 f = -1.209	k = 0.7 α = -0.601 e = 0.8 f = -1.209

2) Male

C value: 1

	Scr≤0.9mg/dL	Scr>0.9mg/dL
Scys<=0.8mg/L	k = 0.9 α = -0.207 e = 0.8 f = -0.375	k = 0.9 α = -0.601 e = 0.8 f = -0.375
Scys>0.8mg/L	k = 0.9 α = -0.207 e = 0.8 f = -1.209	k = 0.9 α = -0.601 e = 0.8 f = -1.209

where:

• Scr: Serum Creatinine (mg/dL)
• Scys: Serum Cyst C (mg/L)

3. Schwartz formula (2009) - Child version

Schwartz formula is specifically used for estimating eGFR in children, mainly based on height and serum creatinine. Applicable to children aged 1-18 years.

Formula:

Height unit is cm, serum creatinine unit is mg/dL.

Notes:

• For serum creatinine values in μmol/L, divide by 88.4 to convert to mg/dL.
• All formula results are in mL/min/1.73m².

Usage Guide

1. Enter patient's age (18-120 years)
2. Select patient's gender (Male/Female)
3. Input serum creatinine value (unit: mg/dL)
4. Click "Calculate" button to get result

Notes:

• MDRD formula applies to 18 years and above adults
• For extremely obese, muscular patients or patients with severe malnutrition or liver cirrhosis, results may not be accurate
• For patients with acute renal injury, eGFR may not accurately reflect kidney function
• If serum creatinine value is in μmol/L, need to be divided by 88.4 to convert to mg/dL

Clinical Meaning

eGFR is chronic kidney disease(CKD) diagnosis and staging important indicator. eGFR less than 60 mL/min/1.73m² over 3 months, can be diagnosed with chronic kidney disease. eGFR monitoring is crucial for assessment of kidney disease progression, treatment dosage adjustment and decision of renal replacement therapy.

Reference

1. Levey AS, et al. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med. 1999;130(6):461-470.
2. National Kidney Foundation. K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis. 2002;39(2 Suppl 1):S1-266.
3. Levey AS, et al. Using standardized serum creatinine values in the modification of diet in renal disease study equation for estimating glomerular filtration rate. Ann Intern Med. 2006;145(4):247-254.
4. KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int Suppl. 2013;3:1-150.

Disclaimer: This calculator is for reference only, and specific medical decisions should be made by professional medical personnel in conjunction with the patient's clinical situation.