Final answer:
The monofilament is not a required tool for assessing a fungal infection on a patient's leg; instead, it is used for sensory testing in cases such as diabetic neuropathy.
Step-by-step explanation:
The tool not required for the assessment of a suspected fungal infection on the patient's leg is the monofilament. A Wood's lamp uses ultraviolet light to cause fungal elements to fluoresce, aiding in the diagnosis of fungal infections such as ringworm. A magnifier can be used to get a better view of the skin's surface during the examination. A ruler may be used to measure the size of the lesion which can be important for documentation and assessment of treatment progress.
The monofilament, on the other hand, is used to assess sensory function, particularly in diabetic patients to test for neuropathy, which is not related to the detection or assessment of fungal infections. Therefore, it is not typically part of the setup for assessing a fungal infection on the skin.