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Explaining the ICN Number

When claims are entered into the Medicare system, they are issued a tracking number known as the internal control number (“ICN”). The ICN is a 13-digit number assigned to each claim received by Medicare. The significance of the digits is as follows:

  • Digits 1-2: Indicate how the claim was submitted (electronically or via paper)
  • Digits 3-4: Indicate the calendar year in which the claim was received
  • Digits 5-7: Indicate the day of the year the claim was received
  • Digits 8-13: Indicate a unique set of numbers assigned by the Medicare contractor

For example, a claim has an ICN of 1114100351480.

  • The third and fourth digits of the ICN are 14, indicating the claim was received in calendar year 2014.
  • The fifth, sixth, and seventh digits of the ICN are 100, indicating the claim was received on the 100th day of the calendar year.

As such, the claim was received by Medicare on April 10, 2014.