Superbills: ICD-9 vs. ICD-10

To show the added complexity that providers will face when using ICD-10-CM, the Blue Cross Blue Shield Association converted a superbill from ICD-9-CM to ICD-10-CM.

• View the original ICD-9-CM superbill
• View the ICD-10-CM superbill created using CMS crosswalks

Important things to understand from this exercise:

1. A superbill is a form used by medical practitioners and clinicians so they can quickly complete and submit the procedure(s) and diagnosis(s) for a patient visit for reimbursement. It is generally customized for a provider office and contains patient information, the most common CPT (procedure) and ICD (diagnostic) codes used by that office, and a section for items such as follow-up appointments, copays, and the provider’s signature.
2. Blue Cross Blue Shield Association started with a model superbill created by the American Academy of Family Practitioner’s practice management journal, Family Practice Management (FPM). The back of the superbill shows 164 ICD-9 diagnosis codes identified by FPM as being those most commonly used by family physicians.
3. About half of the 164 ICD-9 codes on the superbill are general codes such as "unspecified" or "not otherwise specified." These general codes exist so that all information encountered in a medical record can be assigned a code. While they lack the specificity necessary to infer diagnosis details, they are often used on superbills due to space limitations. Continuing their use in ICD-10 will only further prevent realization of the code set’s increased granularity.
4. CMS has published "Generalized Equivalency Mappings" or "crosswalks" that relate every ICD-9 code to one or more ICD-10 codes. We used these crosswalks to convert each ICD-9 code on the superbill to its equivalent ICD-10 code or codes.
5. In some cases the CMS crosswalks were incomplete or possibly inaccurate, and conversion to ICD-10 actually produced far less clinical detail than had been provided by the original ICD-9 code. In these few instances we tried to provide an equivalent mapping, while still using more general ICD-10 codes as is typical with superbills. For example:
   • The AAFP superbill includes the ICD-9 codes for "845.00 Sprained/strained ankle, unspecified". The CMS crosswalk maps this to two codes: 1) "S93.409A Sprain of unspecified ligament of unspecified ankle, initial encounter," and 2) "S93.409D Sprain of unspecified ligament of unspecified ankle, subsequent encounter."However, this is incomplete because it does not include a code for a strained ankle. Therefore, we added 1) "S96.919A Strain of unspecified muscle and tendon at ankle and foot level, unspecified side, initial encounter;" and 2) "S96.919D Strain of unspecified muscle and tendon at ankle and foot level, unspecified side, subsequent encounter."
   • The AAFP superbill includes the ICD-9 codes for "919.0 Abrasion, unspecified"; "924.9 Contusions, unspecified"; and "919.4 Insect bite". The CMS crosswalk simply maps these to either of two catch-all ICD-10 codes, "T07 Unspecified multiple injuries" or "T14.90 Unspecified injury of unspecified body region".Such general diagnosis codes submitted by a provider would be insufficient to determine the medical necessity of a procedure. We therefore listed the most residual ICD-10 codes available for each injury type*, e.g. "S90.519A Abrasion, unspecified ankle; Initial encounter".

* Note that there is no single residual ICD-10 code for an Abrasion, Contusion, or Insect bite, respectively—instead, one can only choose among a number of codes for each injury type such as "Abrasion of [particular body part]".