Reporting Diagnosis on the 1500 with ICD10 should NOT have decimals as they are implied. When reporting diagnosis in block 21 of the 1500 there is a 7 character limit and the use of a decimal will drop the final character of a 7 digit code. Therefore diagnosis on the 1500 should be reported without a decimal and simply the characters with no spacing.
Note the following examples of 3, 4, 5, 6, and 7 character codes.
R51, M545, M9900, M25511, MS134XXA
Below is the Medicare manual reference to the non-use of decimals as well as the NUCC 1500 instruction manual reference
Medicare Claims Processing Manual Chapter 26 - Completing and Processing Form CMS-1500 Data Set
Item 21 - Enter the patient's diagnosis/condition.
For form version 02/12, it may be appropriate to report either ICD-9-CM or ICD-10-CM codes depending upon the dates of service (i.e., according to the effective dates of the given code set).
• The “ICD Indicator” identifies the ICD code set being reported.
Enter the applicable ICD indicator according to the following:
ICD-9-CM diagnosis enter “9”
ICD-10-CM diagnosis enter “0”
Enter the indicator as a single digit between the vertical, dotted lines.
• Do not report both ICD-9-CM and ICD-10-CM codes on the same claim form
• Enter up to 12 diagnosis codes
- Do not insert a period in the ICD-9-CM or ICD-10-CM code.
For chiropractic claims-
Primary diagnosis must be segmental somatic dysfunction M9900 to M9905 however the secondary must be a neuromusculoskeletal diagnosis and form the approved list for your state.
NUCC 1500 Claim Form Manual
ITEM NUMBER 21
TITLE: Diagnosis or Nature of Illness or Injury
Enter the indicator between the vertical, dotted lines in the upper right-hand portion of the field.
Enter the codes left justified on each line to identify the patient’s diagnosis and/or condition. Do not include the decimal point in the diagnosis code, because it is implied. List no more than 12 ICD-9-CM or ICD-10-CM diagnosis codes. Relate lines A - L to the lines of service in 24E by the letter of the line. Use the greatest level of specificity. Do not provide narrative description in this field.