ICD-10 Diagnosis Code Structure

How Does the ICD-10-CM Diagnosis Code Set Differ
from the ICD-9-CM?

  • The code set has been expanded from five positions (first one alphanumeric, others numeric) to seven positions. The codes use alphanumeric characters in all positions, not just the first position as in ICD-9.
  • As of the latest version there are approximately 69,000 ICD-10 codes that impact just DME.
  • The new code set provides a significant increase in the specificity of the reporting, allowing more information to be conveyed in a code.
  • The terminology has been modernized and has been made consistent throughout the code set.
  • There are codes that are a combination of diagnoses and symptoms, so that fewer codes need to be reported to fully describe a condition.

New Structure for ICD-10 Diagnosis Codes

ICD-9-CM Diagnosis Codes ICD-10-CM Diagnosis Codes
No Laterality Laterality – Right or Left account for >40% of codes
3-5 digits
  • First digit is alpha (E or V) or numeric
  • Digits 2-5 are numeric
  • Decimal is placed after the third character
 7 digits
  • Digit 1 is alpha; Digit 2 is numeric
  • Digits 3–7 are alpha or numeric
  • Decimal is placed after the third character
No placeholder characters “X” placeholders
Generic codes (that cover both right and left) Specific codes to cover right and left
Limited Severity Parameters Extensive Severity Parameters
Limited Combination Codes Extensive Combination Codes to better capture complexity
1 type of Excludes Notes 2 types of Excludes Notes

Mapping

One of the most important concerns in the transition from ICD-9-CM to ICD-10-CM codes is there is no clear mapping between ICD-9-CM and ICD-10-CM Code SetsThere are some one-to-one correspondences, but often there are one-to-many, many-to-one, many-to-many, or no correspondence at all.

ICD-9 Code ICD-9 Description ICD-10 Codes ICD-10 Description
72741 Ganglion of joint M67419 Ganglion, unspecified shoulder
M67429 Ganglion, unspecified elbow
M67439 Ganglion, unspecified wrist
M67449 Ganglion, unspecified hand
M67459 Ganglion, unspecified hip
M67469 Ganglion, unspecified knee
M67479 Ganglion, unspecified ankle and foot