Onset-of-symptoms date is a REQUIRED FIELD. If claims are being submitted electronically, a real date MUST be entered in this box. If you are submitting the claims for this patient on paper, and the onset of symptoms was gradual, by entering 11-11-1111 the word GRADUAL will print in box 14 on the paper CMS-1500 form. Note that the electronic clearing houses are not capable of reading the word GRADUAL and will reject claims automatically if 11-11-1111 is entered in this field. Depending on the insurance program, Federal and State laws, rules and regulations, this date may or may not need to be changed periodically. For example, in some States and for Medicare the Onset date is connected to the diagnosis, which should be changed monthly in accordance with changes and improvements in the patient. In other States, or for personal injury cases such as automobile accidents, the Onset date remains unchanged for the entire period of the case. It is up to each practice to learn and apply the State and Federal laws, rules and regulations that apply where the practice is located.