Final answer:
Some concerns regarding a creatinine excretion test include accuracy in people with abnormal fluid levels or health conditions, the influence of muscle mass and diet, and limitations in certain populations.
Step-by-step explanation:
The creatinine clearance test is a commonly used procedure to assess the glomerular filtration rate (GFR), which indicates the kidney's excretory function. Concerns associated with the creatinine excretion test include possible inaccuracies due to the presence of certain conditions such as kidney failure and febrile disease, which can impact blood creatinine or creatinine coefficient levels. Additionally, for an accurate assessment of the GFR, patients must follow specific procedures such as a 24-hour urine collection, which can be influenced by patient compliance and proper technique. Another concern is the correction of creatinine clearance for body surface area to ensure comparability across individuals of different sizes. This correction is important because the normal ranges for creatinine clearance values, which are typically 90-139 ml/min for adult males and 80-125 ml/min for adult females younger than 40 years, will decrease with age.