A set of skills and scope of practice may define a primary care physician, generally including basic diagnosis and treatment of common illnesses and medical conditions. Diagnostic techniques include interviewing the patient to collect information on the present symptoms, prior medical history and other health details, followed by a physical examination. Many PCPs are trained in basic medical testing, such as interpreting results of blood or other patient samples, electrocardiograms, or x-rays. More complex and time-intensive diagnostic procedures are usually obtained by referral to specialists, with special training with a technology or increased experience and patient volume that make a risky procedure safer for the patient. After collecting data, the PCP arrives at a differential diagnosis and, with the participation of the patient, formulates a plan including (if appropriate) components of further testing, specialist referral, medication, therapy, diet or life-style changes, patient education, and follow up results of treatment.