During flu season, flu shots are common in the medical billing world. Like everything else, there are many different flu current procedural terminology codes from which to choose. There are three steps to follow to ensure your flu shot medical billing is completely accurate. The first step is to figure in the age of the patient. Any patient who is age three and above should be given one of two medical billing codes: 90656 or 90658. The medical billing code 90656 stands for: influenza virus vaccine, split, virus, preservative-free, for use in individuals 3 years of age and above, for intramuscularly use. The code 90658 in medical billing means: Influenza …