Final answer:
Dialysis or apheresis catheters used for hemodialysis come in different sizes, typically ranging from 12 to 16 French (Fr).
Step-by-step explanation:
Dialysis or apheresis catheters used for hemodialysis are typically made of a flexible plastic material and are available in different sizes. The size of the catheter depends on several factors, including the patient's blood flow rate and individual needs. Common sizes range from 12 to 16 French (Fr), with Fr denoting the diameter of the catheter. A larger Fr size indicates a larger catheter size. For example, a 14 Fr catheter is larger in diameter than a 12 Fr catheter.