GFR calculator (eGFR, CKD-EPI 2021)

eGFR from serum creatinine (mg/dL or µmol/L), age and sex by the race-free CKD-EPI 2021 equation, with optional cystatin C and the KDIGO G1–G5 stage.

آخر تحديث أمثلة تم التحقق منها: 8

Standardized (IDMS-traceable) value from a blood test.
years
The CKD-EPI equations are validated for adults aged 18 and over.
mg/L
Adds the 2021 creatinine–cystatin C and 2012 cystatin C equations.
خيارات إضافية
Adds the KDIGO albuminuria category and heat-map risk.
جرّب
eGFR (creatinine, CKD-EPI 2021)
mL/min/1.73 m²
eGFR (creatinine, CKD-EPI 2021): 92 mL/min/1.73 m²
عدد صحيح؛ إلى الأقرب، وعند التعادل بعيدًا عن الصفر
GFR category (KDIGO 2024)
G1: normal or high
Creatinine in the other unit
88µmol/L
eGFR assumes stable creatinine. It is unreliable in acute kidney injury, pregnancy, amputation, very high or low muscle mass, and after creatine supplements or a large meat meal.

For a man aged 50 with creatinine 1.00 mg/dL, the 2021 CKD-EPI equation gives an eGFR of 92 mL/min/1.73 m². That is KDIGO category G1: normal or high.

KDIGO GFR categories

G5G4G3bG3aG2G101530456090130eGFRcr 92

eGFR by creatinine for a man aged 50

0501001234Creatinine (mg/dL)eGFR (mL/min/1.73 m²)You: 9260: G3a starts
KDIGO 2024 risk by GFR and albuminuria category الصفوف: 6
GFR categoryمعدل الترشيح الكبيبي المقدر (⁨eGFR⁩)A1 (ACR < 30 mg/g)A2 (30–300)A3 (> 300)
G1 (you)≥ 90LowModerateHigh
G260–89LowModerateHigh
G3a45–59ModerateHighVery high
G3b30–44HighVery highVery high
G415–29Very highVery highVery high
G5< 15Very highVery highVery high
طريقة الحساب S
  1. Constants for men

    κ=0.9,α=−0.302,Scrκ=10.9=1.1111\kappa = 0.9,\quad \alpha = -0.302,\quad \frac{S_{cr}}{\kappa} = \frac{1}{0.9} = 1.1111

    The ratio is 1 or more, so the min term equals 1 and the max term uses −1.200.

  2. CKD-EPI 2021 creatinine equation

    142×1.1111−1.200×0.993850=91.69142 \times 1.1111^{-1.200} \times 0.9938^{50} = 91.69

    KDIGO 2024 asks for eGFR to be reported as a whole number in mL/min/1.73 m².

  3. KDIGO GFR category

    Creatinine eGFR reported as 92 → G1: normal or high. Bands: G1 ≥ 90, G2 60–89, G3a 45–59, G3b 30–44, G4 15–29, G5 < 15.

حول GFR calculator (eGFR, CKD-EPI 2021)

Estimated glomerular filtration rate (eGFR) is the volume of blood plasma the kidneys filter each minute, scaled to a body surface area of 1.73 m². It is calculated from serum creatinine, age and sex with the 2021 CKD-EPI equation, which dropped the race coefficient of the 2009 version; the National Kidney Foundation and the American Society of Nephrology recommend it for adults in the US. With a cystatin C result the 2021 creatinine–cystatin C equation is also computed, and KDIGO 2024 grades the kidneys on that combined value when it is available.

Clinicians use eGFR to stage chronic kidney disease and to adjust drug doses. A 50-year-old man with a creatinine of 1.0 mg/dL (88 µmol/L) has an eGFR of 92, category G1. An eGFR below 60 for more than 3 months is chronic kidney disease, category G3a or worse.

The equations assume creatinine is stable. They read wrong in acute kidney injury, pregnancy, very high or low muscle mass, and after a meat-heavy meal or creatine supplements.

أمثلة محلولة

Man, 50 years, creatinine 1.0 mg/dL

Serum creatinine
1.0
Creatinine unit
mg/dL
العمر
50 years
Sex (for the formula)
Male
eGFR (creatinine, CKD-EPI 2021)
92 mL/min/1.73 m²
GFR category (KDIGO 2024)
G1: normal or high
Creatinine in the other unit
88 µmol/L
Creatinine in the other unit
لا ينطبق

مصدر التحقق: ⁨Python 3.8 decimal: 142 × (1.0/0.9)^−1.200 × 0.9938^50 = 91.691 (NKF 2021 CKD-EPI creatinine equation); 1.0 × 88.4 = 88.40 µmol/L⁩

Woman, 60 years, creatinine 0.8 mg/dL

Serum creatinine
0.8
Creatinine unit
mg/dL
العمر
60 years
Sex (for the formula)
Female
eGFR (creatinine, CKD-EPI 2021)
84 mL/min/1.73 m²
GFR category (KDIGO 2024)
G2: mildly decreased

مصدر التحقق: ⁨Python 3.8 decimal: 142 × (0.8/0.7)^−1.200 × 0.9938^60 × 1.012 = 84.298⁩

Man, 70 years, creatinine 177 µmol/L

Serum creatinine
177
Creatinine unit
µmol/L
العمر
70 years
Sex (for the formula)
Male
eGFR (creatinine, CKD-EPI 2021)
35 mL/min/1.73 m²
GFR category (KDIGO 2024)
G3b: moderately to severely decreased
Creatinine in the other unit
2.00 mg/dL
Creatinine in the other unit
لا ينطبق

مصدر التحقق: ⁨Python 3.8 decimal: 177 / 88.4 = 2.00226 mg/dL; 142 × (2.00226/0.9)^−1.200 × 0.9938^70 = 35.195⁩

Woman, 45 years, creatinine 0.6 mg/dL, cystatin C 0.9 mg/L

Serum creatinine
0.6
Creatinine unit
mg/dL
العمر
45 years
Sex (for the formula)
Female
Serum cystatin C (optional)
0.9 mg/L
eGFR (creatinine, CKD-EPI 2021)
113 mL/min/1.73 m²
eGFR (creatinine–cystatin C, 2021)
103 mL/min/1.73 m²
eGFR (cystatin C only, 2012)
89 mL/min/1.73 m²
GFR category (KDIGO 2024)
G1: normal or high

مصدر التحقق: ⁨Python 3.8 decimal: eGFRcr = 142 × (0.6/0.7)^−0.241 × 0.9938^45 × 1.012 = 112.735; eGFRcr-cys = 135 × (0.6/0.7)^−0.219 × (0.9/0.8)^−0.778 × 0.9961^45 × 0.963 = 102.910; eGFRcys = 133 × (0.9/0.8)^−1.328 × 0.996^45 × 0.932 = 88.513⁩

الأسئلة

What is a normal eGFR?

90 mL/min/1.73 m² or higher is KDIGO category G1, normal or high, and 60 to 89 is G2, mildly decreased. Neither counts as chronic kidney disease unless there is also kidney damage, such as albumin in the urine, lasting at least 3 months. The equation lowers eGFR by 0.62 % for each year of age, so the same creatinine of 1.0 mg/dL gives a man 92 at age 50 and 81 at age 70.

What eGFR indicates kidney disease?

An eGFR below 60 mL/min/1.73 m² that lasts more than 3 months meets the KDIGO 2024 definition of chronic kidney disease on its own. KDIGO grades it G3a (45–59), G3b (30–44), G4 (15–29) and G5, kidney failure (below 15). A single low reading is not a diagnosis, because acute illness, dehydration or a recent large meat meal can lower eGFR temporarily; KDIGO asks for repeat testing to confirm.

Why was race removed from the eGFR equation?

The 2009 CKD-EPI equation multiplied eGFR by 1.159 for Black patients, a coefficient based on race as a social category. A joint National Kidney Foundation and American Society of Nephrology task force recommended in 2021 that US labs switch to the refitted 2021 equation, which uses creatinine, age and sex only. KDIGO 2024 practice point 1.2.4.2 says race should not be used to compute eGFR.

When should cystatin C be used to estimate GFR?

When creatinine is likely to mislead. KDIGO 2024 Table 8 lists eating disorders, bodybuilding, above-knee amputation, spinal cord injury, vegetarian or high-protein diets and creatine supplements, among others. KDIGO recommends that when cystatin C is available the GFR category be taken from the combined creatinine–cystatin C equation, which is closer to measured GFR than either marker alone. A large gap between eGFRcr and eGFRcys is itself a signal that one of them is off.

How do you convert creatinine from µmol/L to mg/dL?

Divide by 88.4, the factor in the KDIGO 2024 conversion table; it is 10,000 divided by the molar mass of creatinine, 113.12 g/mol. A result of 88 µmol/L is 1.00 mg/dL and 150 µmol/L is 1.70 mg/dL. KDIGO asks labs to report creatinine to the nearest whole number in µmol/L and to two decimals in mg/dL.

ما مدى دقة «⁨GFR calculator (eGFR, CKD-EPI 2021)⁩»؟

تعتمد الدقة على مدخلاتك وافتراضات الطريقة. يستخدم الحساب العشري 50 رقمًا معنويًا، لكن التقديرات والأساليب العددية وبيانات المصدر قد تكون أقل دقة؛ تقريب القيم المعروضة لا يزيل هذه الحدود. أمثلة محلولة جرى التحقق منها بمصادر مستقلة: 8. مثلًا، يجري التحقق من «⁨Man, 50 years, creatinine 1.0 mg/dL⁩» بالرجوع إلى ⁨Python 3.8 decimal: 142 × (1.0/0.9)^−1.200 × 0.9938^50 = 91.691 (NKF 2021 CKD-EPI creatinine equation); 1.0 × 88.4 = 88.40 µmol/L⁩.

ما مصدر هذه الطريقة؟

Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–1749; National Kidney Foundation — CKD-EPI creatinine equation (2021); National Kidney Foundation — CKD-EPI creatinine–cystatin C equation (2021); National Kidney Foundation — CKD-EPI cystatin C equation (2012); KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 2024;105(4S):S117–S314; Delgado C et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force. Am J Kidney Dis 2022;79:268–288.

حول هذه الحاسبة

eGFRcr=142×min⁡ ⁣(Scrκ,1)α×max⁡ ⁣(Scrκ,1)−1.200×0.9938age×1.012 [female]\text{eGFR}_{cr} = 142 \times \min\!\left(\tfrac{S_{cr}}{\kappa},1\right)^{\alpha} \times \max\!\left(\tfrac{S_{cr}}{\kappa},1\right)^{-1.200} \times 0.9938^{\text{age}} \times 1.012\ [\text{female}]

المصادر

  1. Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–1749
  2. National Kidney Foundation — CKD-EPI creatinine equation (2021)
  3. National Kidney Foundation — CKD-EPI creatinine–cystatin C equation (2021)
  4. National Kidney Foundation — CKD-EPI cystatin C equation (2012)
  5. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int 2024;105(4S):S117–S314
  6. Delgado C et al. A unifying approach for GFR estimation: recommendations of the NKF-ASN Task Force. Am J Kidney Dis 2022;79:268–288

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