What should you check before mixing the diluent with the vaccine?

It is essential to check the expiration date before mixing the diluent with the vaccine because using an expired vaccine can lead to ineffective immunization. Vaccines have specific stability profiles, and their potency can diminish over time, rendering them less effective or even ineffective once they pass their expiration date. Ensuring that both the vaccine and diluent are within their viable date range is crucial for patient safety and maximizing the vaccine's efficacy.

While other factors, such as the order of administration, the patient's health history, and the volume of diluent, are important considerations in the overall vaccination process, they do not directly pertain to the safety and effectiveness of the vaccine itself at the point of mixing. The expiration date is a primary concern to ensure that the immunization is both safe and effective.