what is an icn number
When claims are entered into the Medicare system, they are issued a tracking number known as the internal control number (âICNâ). The ICN is a 13-digit number assigned to each claim received by Medicare. The significance of the digits is as follows: 1  Digits 1-2: Indicate how the claim was submitted (electronically or via paper). 2  Digits 3-4: Indicate the calendar year in which the claim was received.