In which situation is a nursing assistant unable to cut a patient's nails?

A nursing assistant is unable to cut a patient's nails in the case of a patient who has diabetes. This is due to the potential complications associated with diabetes, particularly concerning foot and nail care. Individuals with diabetes are at a higher risk for infections and complications with their feet, including neuropathy and poor circulation. As a result, nail care for diabetic patients must be performed with caution and typically requires the expertise of a nurse or a podiatrist to avoid injury or infection.

In contrast, a patient having a cold, being on medication, or having an infection might not directly impact the safety or appropriateness of nail cutting, although those scenarios may have their own considerations. However, when it comes to diabetes specifically, the risk factors involved necessitate a higher standard of care for nail maintenance.