What action should a nurse take to effectively assess a patient's pain level?

To effectively assess a patient's pain level, determining the location of the pain is crucial. Understanding where the pain is located helps the nurse gauge its severity and potential causes. Pain is a subjective experience, and pinpointing its location provides a starting point for further assessment and communication with the patient. This information can guide treatment decisions and interventions.

The other response options, while they may have their own importance in different contexts, do not directly contribute to an effective pain assessment. Knowledge of family history may offer insights into genetic predispositions or chronic conditions, but it does not provide immediate information about the patient's current pain experience. Taking vital signs could be part of a general assessment but does not address the patient's pain specifically. Requiring a written note about the pain might hinder the assessment process, as it can create barriers to open communication and immediate understanding of the patient's situation.