Health plans across the nation are enlisting armies of nurses and social workers to keep an eye on their members’ care. These care managers work with doctors to make sure patients get the screening tests they need, don’t take unnecessary drugs and go to specialty doctors only when merited. According to UPMC Health Plan President Diane Holder, care managers are part of a new model of care called medical homes that in one year alone saved the health plan more than $15 million. The insurer employs 72 such workers at UPMC and non-UPMC practices. Experts say the success of care managers will depend not just on their ability to enhance the patient’s experience but also on whether they can cut costs and avoid unnecessary treatment.