ICD-10-CM codes are used for providers of professional services like physicians, physician assistants, nurse practitioners, psychiatrists, therapists, and other qualified healthcare professionals. ICD-10-CM codes are required on all CMS-1500 claim forms to report the medical reason why a procedure or service was performed for a specific patient. Should the diagnosis(es) reported not meet what the insurance company considers the medical necessity for the procedure or service, the claim will likely be denied for payment, leaving the provider with no reimbursement for his/her services. ICD-10-CM codes can be found in insurance company policies as part of the information in which a procedure or service will be paid for a procedure or service. The ICD-10-CM manual has 3 parts. There are official guidelines that instruct users how to choose and sequence ICD-10-CM codes, as well as an alphabetical listing to allow users to locate a specific code, and a tabular listing of the ICD-10-CM codes for the user to reference for instructions related to the code being considered. While there once was a grace period in the implementation of the annual code changes to ICD-10-CM, that is no longer an option, and the 2020 codes are in effect for any claim with a date of service October 1, 2019, and beyond.

These changes have a direct effect on medical claims and also attribute to payments for services rendered by medical providers. It is important to assign the correct diagnosis codes to show medical necessity for the services rendered. New codes have been added, that in some cases replace or expand current codes. Other codes are being deleted because of lack of use, and more specific codes are now available. New diseases and conditions also require that codes be assigned in order for medical providers to be able to code diagnoses to the highest level of specificity.