Hello, I am looking for guidance/documentation on what the valid format is for HICN. We have several clients that are expecting patients to qualify for HWR/HWM, but the HICN provided is in an invalid format (ex: H12345678 alpha followed by 8 digits). I was searching on the CMS website looking for guidance with no luck, but I did find the following page that gives an explanation, but I don't think this is from a website that I can share with clients (i.e. not directly from CMS website). https://medicarepaymentandreimbursement.com/2010/05/medicare-hic-number-suffixes.html#:~:text=Health%20Insurance%20Claims%20Numbers%20(HICNs)&text=If%20there%20is%20an%20eleventh,or%20MA123%2D45%2D6789 . Any documentation around this topic to help our clients understand the correct formatting would be helpful.