Question

Creatine clearance Worksheet

Refer to page 14 of your textbook for reference and calculations

For each of these questions calculate the creatine clearance using the most appropriate method

John Sanders DOB 4-17-91

Patient’s urine creatine- 569mg/day

Patient’s plasma creatine- 3.69mg/dL

Total volume-729ml/24 hours

Debbie Renninger DOB 7-19-86

Patient’s urine creatine- 1179 mg/day

Patient’s plasma creatine-5.79 mg/dL

Total volume- 2253mL/24 hours

Samantha Pierson DOB 8-25-76

Patient’s urine creatine- 1589 mg/day

Patient’s plasma creatine- 7.73 mg/dL

Total volume- 785mL/24 hours

Wesley Matthews DOB 7-5-2013

Patient’s urine creatine- 1225 mg/day

Patient’s plasma creatine- 6.59 mg/dL

Total volume- 1117mL/24 hours

Answer 1

The Formula for Creatinine Clearance =

Creat Clear = (Urine Creatinine x Day’s Urine) / (Serum Creatinine x 1440)

Where 1440 is a day’s time in minutes(ie; 24 x 60 =1440 minutes)

Case 1 (John Sanders)

Urine Creatinine = 569 mg/dL

Serum Creatinine = 3.69 mg/dL

Day’s Urine Volume = 729 mL

Creatinine Clearance = (569 x 729) / (3.69 x 1440)

            = 414,801 / 5313.6

            = 78.06 m L/min.

Case 2 (Debbie Renninger)

Urine Creatinine = 1179 mg/dL

Serum Creatinine = 5.79 mg/dL

Day’s Urine Volume = 2253 mL

Creatinine Clearance = (1179 x 2253) / (5.79 x 1440)

            =2656287 / 8337.6

            =318.59 mL/min

Case 3 (Samantha Pierson)

Urine Creatinine = 1589 mg/dL

Serum Creatinine = 7.73 mg/dL

Day’s Urine Volume = 785 mL

Creatinine Clearance = (1589 x 785) / (7.73 x 1440)

            = 112.06 mL/min

Case 4 (Wesley Matthews)   

Urine Creatinine = 1225 mg/dL

Serum Creatinine = 6.59 mg/dL

Day’s Urine Volume = 1117 mL

Creatinine Clearance = (1225 x 1117) / (6.59 x 1440)

            = 144.19 mL/min