Which of the following must be documented in the progress note of this patient's electronic health record?

While the date of the last office visit is important for understanding the patient's medical history and treatment plan, it is not mandatory for documentation in a progress note specifically related to a call. The focus of the progress note should be on the interaction at hand rather than past visits.

The patient's date of birth is an important identifier but does not need to be documented in every progress note. It is typically recorded in the patient's demographic information rather than in each individual progress note, as it does not pertain directly to the content of the call.

While knowing the primary care physician's name can be helpful for continuity of care, it is not a required element to be noted in the progress documentation for a specific patient call. This information is usually found in the patient's record rather than needing to be reiterated in every progress note.

Recent laboratory results are relevant to patient care but are not necessary to document during a call progress note unless they are specifically discussed or influence the call's context. The focus of the note should be on the call's details rather than summarizing laboratory data.