Renal Function Estimation

MM is a 43 year-old male patient who is 5’8” and weighs 155 lb. His SCr is 1.8mg/dL. Calculate his creatinine clearance with the Cockcroft-Gault equation using the ideal body weight.

• 50.90 mL/min

• 113.15 mL/min

• 52.39 mL/min

• 120.90 mL/min

Calculate the creatinine clearance for a 55-year-old female patient who is 5’4” and weighs 150 lbs. Her SCr is 1.2mg/dL. Use the Cockcroft-Gault equation with the most appropriate weight.

• 72.45 ml/min

• 65.30 mL/min

• 50.17 mL/min

• 80.10 mL/min

Answer explanation

Based on BMI of this patient = 25.6, she is overweighted and AdjBW should be used for CrCl rate calculation.

IBW = 55 kg and AdjBW = 60 kg

Thus, the estimated clearance is 50.17 mL/min.

Using the Cockcroft-Gault equation, determine the creatinine clearance for a 60-year-old male who is 6’0” and weighs 200 lbs. His SCr is 2.0mg/dL. Choose the correct weight for calculation.

• 50.55 mL/min

• 46.11 mL/min

• 43.33 mL/min

• 52.10 mL/min

Answer explanation

Because BMI for this male patient 27.1, which is >25, AdjBW should be used for CrCl rate calculation.

Using AdjBW = 83 kg, the estimated clearance is 46.11 mL/min.

A 70-year-old female patient is 5’6” and weighs 108 lbs. Her SCr is 1.5mg/dL. Calculate her creatinine clearance using the Cockcroft-Gault equation with the appropriate weight.

• 45 mL/min

• 27 mL/min

• 32 mL/min

• 37 mL/min

Answer explanation

Based on BMI = 17.4, this patient is underweight and therefore TBW should be used for CrCl estimation.

Converting weight to kg (108 lbs = 49 kg),

CrCl = [(140-70) x 49] / (72 x 1.5) * 0.85 = 27 mL/min, which is the correct answer.

Calculate the CrCl via the Schwartz equation for Samuel, a 24-month-old male who is 82 cm long with SCr of 0.5mg/dL.

• 82.1 mL/min

• 90.2 mL/min

• 75.4 mL/min

• 105.8 mL/min

Answer explanation

To calculate CrCl using the Schwartz equation: CrCl = (K * length in cm) / SCr. For a 24-month-old male, K = 0.55. Plugging in the values: CrCl = (0.55 * 82) / 0.5 = 90.2 mL/min, which is the correct answer.

Calculate the CrCl via the Schwartz equation for Emma, 14 YOF, who is 64" tall with SCr of 0.5mg/dL.

• 179 mL/min

• 121 mL/min

• 70 mL/min

• 227 mL/min

Answer explanation

To calculate CrCl using the Schwartz equation: CrCl = (K * height in cm) / SCr. For a 14-year-old girl, K is typically 0.55. Converting 64" to cm, CrCl = (0.55 * 163 cm) / 0.5 mg/dL = 178.82 mL/min