Creatinine Clearance

Aka: Creatinine Clearance, Glomerular Filtration Rate, GFR, CrCl, Cockcroft-Gault, Modification of Diet in Renal Disease, MDRD, Chronic Kidney Disease Epidemiology Collaboration, CKD-EPI

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II. Indications

  1. Creatinine Clearance estimates Glomerular Filtration Rate (GFR)

III. Interpretation: Normal Creatinine Clearance

  1. Men
    1. Average: 120 ml/min/1.73 m2 (+/-25) or 175 Liters/day
    2. Range: 97-137 ml/min/1.73 m2 (0.93-1.32 ml/sec/m2 IU)
  2. Women
    1. Average: 95 ml/min/1.73 m2 (+/-20) or 135 Liters/day
    2. Range: 88-128 ml/min/1.73 m2 (0.85-1.23 ml/sec/m2 IU)

IV. Calculation: Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)

  1. Calculation
    1. Males: 141 * min (sCr/0.9 or 1) ^ -0.411 * max(sCr/0.9 or 1)^ - 1.209 * 0.993 ^ ageY
    2. Females: 141 * min (sCr/0.7 or 1) ^ -0.329 * max(sCr/0.7 or 1)^ - 1.209 * 0.993 ^ ageY * 1.018
    3. Black: Multiply above equation (based on gender) by 1.159
      1. Applying black race variable is NOT recommended
  2. Annotation
    1. Where sCr is Serum Creatinine
    2. Min is the minimum value (either that calculated or 1)
    3. Max is the maximum value (either that calculated or 1)
    4. Where ^ represents to the power of...
  3. Efficacy
    1. More accurate than either CKD or MDRD
    2. Preferred method of eGFR calculation (without race variable)
  4. Alternatives
    1. GFR may also be estimated from Serum Cystatin C instead of Serum Creatinine
      1. Consider if abnormal GFR based on Creatinine Clearance suspected to be False Positive
  5. Resources
    1. National Kidney Foundation
      1. https://www.kidney.org/professionals/kdoqi/gfr_calculator
  6. References
    1. Levey (2009) Ann Intern Med 150(9): 604-12 [PubMed]

V. Calculation: Cockcroft-Gault formula for GFR estimate

  1. Indications: Stable Kidney Function
    1. As of 2017, primarily used only for medication Renal Dosing (other calculations are preferred)
    2. Older patients
    3. General screening
  2. Male GFR = (140 - age) x (weight) / (sCr x 72)
  3. Female GFR = (140 - age) x (weight) x 0.85 / (sCr x 72)
  4. Annotation
    1. Where GFR is Glomerular Filtration Rate in ml/min
    2. Where age is in years
    3. Where weight is Lean Body Mass in kilograms
    4. Where sCr is Serum Creatinine in mg/dl
  5. Efficacy
    1. As accurate as 24 hour urine in most cases
    2. Exceptions: See 24 hour CrCl indications below
  6. Resources: GFR Calculator
    1. http://www.kidney.org/kls/professionals/

VI. Calculation: Abbreviated MDRD Study Equation

  1. Indications: Chronic Kidney Disease, stable function
    1. Middle aged patients
    2. Black patients
    3. Diabetic Nephropathy
    4. Status-post Kidney Transplant
  2. Efficacy
    1. More accurate than Cockroft-Gault in CRF
      1. Levey (1999) Ann Intern Med 130:461-70 [PubMed]
    2. Overestimates Chronic Kidney Disease when used as a general screening tool
      1. Underestimates GFR in the absence of Kidney disease
      2. Rule (2004) Ann Intern Med 141:929-37 [PubMed]
  3. Formula: GFR = 186 x (sCr)^-1.154 x (age)^-0.203
    1. Where sCr is raised by power of -1.154
    2. Where age is raised by power of -0.203
  4. Modifiers
    1. Female: Multiply GFR by 0.742
    2. Black: Multiply GFR by 1.210
  5. Annotation
    1. Where GFR=Glomerular Filtration Rate ml/min/1.73 m2
    2. Where sCr is Serum Creatinine in mg/dl

VII. Calculation: 24 hour Creatinine Clearance

  1. Previously considered gold standard GFR evaluation
    1. Now thought to be less accurate than calculations (see above) due to flawed collection
  2. Indications
    1. Pregnancy
    2. Severely underweight or Overweight
    3. Very young and very old
    4. Malnutrition
    5. Skeletal Muscle disorders, Paraplegia, Quadriplegia
  3. Formula
    1. CrCl = (uCr x uV) / (sCr x 1440)
  4. Annotation
    1. Where CrCl is Creatinine Clearance in ml/min
    2. Where uCr is Urine Creatinine in mg/dl
    3. Where sCr is Serum Creatinine in mg/dl
    4. Where uV is 24 hour Urine Volume in ml
    5. Where 1440 represents number of minutes in 24 hours
  5. Indications (where calculation above is inaccurate)
    1. Altered Protein intake
      1. Vegetarian Diet
      2. Creatine Supplementation
    2. Altered Muscle mass
      1. Malnutrition or Muscle wasting
      2. Amputation

VIII. Interpretation: Increased GFR

  1. Pregnancy
  2. Exercise

IX. Interpretation: Decreased GFR

  1. Chronic Kidney Disease or Renal Insufficiency
  2. Advanced age
    1. Normal GFR is 125 ml/min/1.73 m2 at age 30 years
    2. GFR decreases by 1 ml/min/year over age 30 years
  3. Inadequate urine specimen collection
    1. See Urine Creatinine for judging adequacy
  4. Medications (Decrease tubular secretion of Creatinine)
    1. Cimetidine
    2. Procainamide
    3. Antibiotics
    4. Quinidine

X. Precautions: Pitfalls

  1. Creatinine Clearance (CrCl) and estimated Glomerular Filtration Rate (eGFR) are NOT interchangeable
    1. Older dosing guidelines and precautions were given in CrCl, but newer guidelines refer to eGFR
      1. CrCl units are ml/min
      2. eGFR units are ml/min/1.73m^2
    2. Drug dosing guidelines are specific for their cutoff ranges
      1. Using eGFR when CrCl is indicated will miss dose adjustments in up to 50% of cases
      2. Highest risk for miscalculation is in the elderly and in moderate to severe Chronic Kidney Disease
  2. Calculating GFR in specific cohorts
    1. As of 2020, guidelines recommend calculating eGFR without regard to race
    2. Overweight (bodyweight >20-30% over Ideal Weight)
      1. Calculate based on adjusted body weight
      2. Adjusted body weight = wtKgIdeal + 0.4 * (wtKgActual - wtKgIdeal)
    3. Underweight
      1. Use actual weight
      2. Do not round up when calculating CrCl (significantly underestimates GFR)
    4. Alternative calculation for patients well above or below their Ideal Body Weight
      1. Corrected eGFR = eGFR * BSA/1.73 m2
    5. Elderly
      1. Do not round up when calculating CrCl (significantly underestimates GFR)
    6. Limb Amputation or Quadriplegic
      1. Measure 24 hour Creatinine Clearance
    7. Abnormal Creatinine Clearance suspected to be False Positive
      1. Serum Cystatin C may be used as alternative to Serum Creatinine
  3. Creatinine Clearance (by 24 hour urine) is overestimated at decreased GFR
    1. As GFR decreases, secreted Creatinine makes up larger percentage of total Urine Creatinine
    2. Consider pre-medicating the 24 hour Urine Collection
      1. Give Cimetidine or Trimethoprim for 2 days prior to 24 hour Urine Collection
      2. Overcomes the over-estimatation of GFR

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Related Studies

Ontology: Glomerular Filtration Rate (C0017654)

Definition (NCI_CDISC) A kidney function test that measures the fluid volume that is filtered from the kidney glomeruli to the Bowman's capsule per unit of time.
Definition (NCI) A kidney function test that measures the fluid volume that is filtered from the kidney glomeruli to the Bowman's capsule per unit of time.
Definition (MSH) The volume of water filtered out of plasma through glomerular capillary walls into Bowman's capsules per unit of time. It is considered to be equivalent to INULIN clearance.
Definition (CSP) rate at which plasma is filtered by the glomerular filtration membrane into Bowman's space; determined by the permeabiliy of the membrane, hydrostatic pressure in the glomerular capillaries and Bowman's space, and the colloid osmotic pressure exerted by the proteins of the capillary plasma.
Concepts Diagnostic Procedure (T060)
MSH D005919
SnomedCT 80274001
LNC LP69203-5
English Filtration Rate, Glomerular, Filtration Rates, Glomerular, Glomerular Filtration Rates, Rate, Glomerular Filtration, Rates, Glomerular Filtration, glomerular filtration rate, GFR, gfr, rate filtration glomerular, filtration glomerular rate, Glomerular filtration rate, Glomerular filtration rate (observable entity), Glomerular filtration rate, NOS, Glomerular filtration rate (function), Glomerular filtration rate, function (observable entity), Glomerular Filtration Rate
Italian Velocità di filtrazione glomerulare, Filtrato glomerulare renale, Percentuale di filtrato glomerulare
Dutch GFR, glomerulaire filtratiesnelheid, Filtratiesnelheid, glomerus-, Glomerusfiltratiesnelheid
French TFG (taux de filtration glomérulaire), TFG (Taux de Filtration Glomérulaire), Taux de filtration glomérulaire, Débit de filtration glomérulaire
German GFR, glomerulaere Filtrationsrate, Glomeruläre Filtrationsrate
Portuguese Taxa de filtração glomerular, Fracção de filtração glomerular, Taxa de Filtração Glomerular
Spanish TFG, tasa de filtración glomerular (entidad observable), tasa de filtración glomerular (función), tasa de filtración glomerular, Tasa de filtración glomerular, Tasa de Filtración Glomerular
Japanese 糸球体濾過率, ＧＦＲ, ｼｷｭｳﾀｲﾛｶﾘﾂ, GFR
Swedish Glomerulär filtrationshastighet
Czech glomerulární filtrace - hodnota, Glomerulární filtrace, GFR
Finnish Glomerulusten suodattumisnopeus
Russian KLUBOCHKOVOI FIL'TRATSII SKOROST', POCHECHNYKH KLUBOCHKOV FIL'TRATSII SKOROST', КЛУБОЧКОВОЙ ФИЛЬТРАЦИИ СКОРОСТЬ, ПОЧЕЧНЫХ КЛУБОЧКОВ ФИЛЬТРАЦИИ СКОРОСТЬ
Croatian GLOMERULARNA FILTRACIJA
Polish Współczynnik filtracji kłębuszkowej, Wielkość przesączania kłębuszkowego, GFR, Wskaźnik filtracji kłębuszkowej, Przesączanie kłębuszkowe, Filtracja kłębuszkowa, Klirens kreatyniny
Hungarian Glomeruláris filtrációs ráta, GFR
Norwegian Glomerulær filtrasjonsrate
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Creatinine clearance measurement (C0373595)

Definition (NCI_CDISC) A measurement of the volume of serum or plasma that would be cleared of creatinine by excretion of urine for a specified unit of time (e.g. one minute).
Definition (NCI) The determination of the clearance of endogenous creatinine, used for evaluating the glomerular filtration rate.
Concepts Laboratory Procedure (T059)
SnomedCT 167181009, 167187008, 144424006, 104614007, 270011004, 74481005
CPT 82575
English Creatinine; clearance, Creatinine renal clearance, renal function creatinine clearance (procedure), creatinine clearance, renal function creatinine clearance, Creatinine clearance, Measurement of renal clearance of creatinine, Creatinine clearance test, Measurement of renal clearance of creatinine (procedure), Creatinine clearance measurement, creatine clearance, creatinine clearance test, clearance creatine, Creatinine clearance test (procedure), Creatinine renal clearance measurement (procedure), Creatinine clearance-glom filt, Creatinine clearance study (procedure), Creatinine renal clearance measurement, Creatinine clearance study, CREATCLR, CREATININE CLEARANCE TEST, Creatinine Clearance, CREATININE CLEARANCE
Italian Clearance renale della creatinina, Clearance della creatinina
Dutch creatinineklaring, creatinineklaring, renaal
Portuguese Clearance da creatina, Clearance renal da creatina
Spanish Aclaramiento de creatinina, medición de depuración renal de creatinina, medición de depuración renal de creatinina (procedimiento), prueba de depuración de creatinina, prueba de depuración de creatinina (procedimiento), aclaramiento, estudio de depuración de creatinina (procedimiento), medición de la depuración renal de creatinina (procedimiento), medición de la depuración renal de creatinina, estudio de depuración de creatinina, prueba de aclaramiento de creatinina, prueba de clearance de creatinina, Aclaramiento renal de creatinina
Japanese クレアチニン・クリアランス, 腎クレアチニン・クリアランス, ｸﾚｱﾁﾆﾝｸﾘｱﾗﾝｽ, ｼﾞﾝｸﾚｱﾁﾆﾝｸﾘｱﾗﾝｽ
Czech Clearance kreatininu, Clearance kreatininu renální
Hungarian Kreatinin vese clearance, Kreatinin clearance
French Clairance de la créatinine
German Kreatininclearance
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Glomerular filtration rate/1.73 sq M.predicted:ArVRat:Pt:Ser/Plas:Qn:Creatinine-based formula (MDRD) (C1316377)

Concepts Clinical Attribute (T201)
LNC 33914-3
English Glomerular filtration rate/1.73 sq M.predicted by Creatinine-based formula (MDRD), GFR/BSA.pred SerPl MDRD-ArVRat, Glomerular filtration rate/1.73 sq M.predicted:ArVRat:Pt:Ser/Plas:Qn:Creatinine-based formula (MDRD), Glomerular filtration rate/1.73 sq M.predicted:Volume Rate/Area:Point in time:Serum/Plasma:Quantitative:Creatinine-based formula (MDRD)
Derived from the NIH UMLS (Unified Medical Language System)

Ontology: Estimation of creatinine clearance by Cockcroft-Gault formula (C2711451)

Concepts Laboratory Procedure (T059)
SnomedCT 442407001
English Estimation of creatinine clearance by Cockcroft-Gault formula, Estimation of creatinine clearance by Cockcroft-Gault formula (procedure)
Spanish estimación de la depuración de creatinina mediante la fórmula de Cockcroft-Gault, estimación de la depuración de creatinina mediante la fórmula de Cockcroft-Gault (procedimiento)
Derived from the NIH UMLS (Unified Medical Language System)

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