Different payers require use of different forms each of which has its own instructions. In addition, about a year ago the system of coding changed from ICD-9 to ICD-10 which added a large number of codes to improve specificity, but also failed to include codes that would have added specificity to certain things, such as for HD and PD access infections.
Many patients on dialysis have Medicare. There are Medicare manuals that explain Medicare benefits (Medicare Benefit Policy Manual) and how to file a claim (Medicare Claims Processing Manual). Manuals for different provider/supplier types can be found at https://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Internet-Only-Manuals-IOMs.html.