Maximum Diagnosis Codes Submission on Claim Forms

We are frequently asked by clients and others in the industry about the number of diagnosis codes allowed on the electronic format as well as the paper forms when billing for services. This is especially true in risk adjustment where all current diagnoses are collected for financial forecasting purposes. Some try to use claim editing to capture these but ultimately a medical record review by an experience risk adjustment coding team is still the best method to capture all current diagnoses. Provider offices can make mistakes in capturing diagnoses that are incorrect or should not be reported while also submitting unspecified diagnosis codes when the specificity is documented.

When billing, there are various types of forms that are frequently used by different organizations.

  • The UB-40 (CMS 1450): is a claim form used by hospitals, nursing facilities, in-patient, and other facility providers. A specific facility provider of service may also use this type of form. (Note the UB-40 allows for up to eighteen (18) diagnosis codes.)
  • The HCFA-1500 (CMS 1500): is a medical claim form used by individual doctors & practice, nurses, and professionals including therapists, chiropractors and outpatient clinics. It is not typically hospital-oriented.
  • ANSI ASC X12N 837P: The American National Standards Institute (ANSI) Accredited Standards Committee (ASC) X12N 837P (Professional) Version 5010A1 is the current electronic claim version. The 837P (professional) is the standard format used by healthcare professionals and suppliers to transmit health care claims electronically. (It is thought of as the electronic version of the 1500 paper form.)

The 5010 and CMS-1500 forms were modified to support up to 12 diagnosis codes per claim (while maintaining the limit to four diagnosis code pointers) in an effort to reduce paper and electronic claims from splitting. This change was never intended to increase the number of diagnosis codes per line item. (note that before this change, the 4010 supported up to eight (8) unique diagnosis codes per claim, and the older CMS-1500 supported four (4). Any codes exceeding those limits would split the 837 into two (2) claims and paper claims into three (3). Increasing the total of supported diagnosis codes on the claim format helped to reduce the amount of claims splitting and this helped alleviate costs for both payers and practices.

With the implementation of ANSI 5010 electronic format and the revised CMS 1500 (2/12) paper form a few years ago, many organizations have edited their EMR or billing systems to allow up to twelve (12) diagnosis codes per claim as required in the electronic and paper formats. Although twelve diagnosis codes are allowed per claim, only four diagnosis codes are allowed per line item (each individual procedure code).

•   ONLY four (4) diagnosis codes may connected (pointed) to each procedure.

There are examples where more than four (> 4) diagnosis codes on a claim is vital to documenting the full extent of a patient’s illness or injuries. While there are 12 places holders for diagnoses, only a maximum of four (4) is allowed for each single procedure performed. This means there can be up to 8 “floating diagnoses” that are captured as current diagnoses of the patient, that may be additional diagnoses related to the charges (but unable to be pointed to them as 4 are already pointing to the procedure), or they may be additional diagnoses related to the Medical Decision Making (MDM) of the visit as current other comorbidities.

You can see an example of a CMS 1500 paper form below. Note that Box 21 can be populated with 12 diagnosis codes. Box 24E will only allow up to four diagnosis pointers.

CMS released a guide in January 2015 on PQRS Claims-Based Coding and Reporting Principles that can be found here:


The NUCC (National Uniform Claim Committee) requirements can be found here: