If an 80-year-old female patient has a serum creatinine of 1.0 mg/dL and her ideal body weight is 110 lb, what is the estimated creatinine clearance using the Cockcroft-Gault equation?

To estimate creatinine clearance using the Cockcroft-Gault equation, it is essential to apply the equation accurately, which is designed to estimate renal function based on serum creatinine, age, weight, and gender.

For the Cockcroft-Gault equation, the formula for men is:

[

C_{cr} = \frac{(140 - \text{age}) \times \text{weight (kg)}}{72 \times \text{serum creatinine (mg/dL)}}

]

For women, the equation is adjusted by multiplying the result by 0.85:

[

C_{cr} = \left( \frac{(140 - \text{age}) \times \text{weight (kg)}}{72 \times \text{serum creatinine (mg/dL)}} \right) \times 0.85

]

In this case, the patient is an 80-year-old female weighing 110 lb. To apply the formula, we must convert weight from pounds to kilograms. 110 lb divided by 2.2 equals approximately 50 kg.

Next, we substitute the values into the female version of the Cockcroft-Gault equation:

1. Calculate ( 140 - \