Official documentation
ICD-10-CM Official Guidelines for Coding and Reporting FY 2027
Centers for Medicare and Medicaid Services and National Center for Health Statistics, U.S. Department of Health and Human Services (CMS and CDC NCHS), 2026
Read the originalRead on October 17, 2026
- What it is
- The official U.S. rules for assigning ICD-10-CM diagnosis codes, updated for federal fiscal year 2027, which runs from October 1, 2026 to September 30, 2027. Section I.B.13 covers laterality, meaning which side of the body a code refers to.
- How much weight it carries
- Issued jointly by the two federal agencies that maintain ICD-10-CM and updated each year. It sets the rules but not the full code tables, which come in separate files from the same release. It is a coding reference, not a clinical or legal source.
Facts taken from this source
- When both sides are treated in separate encounters, the official guidelines still use the bilateral code, because the condition still exists on both sides.
“as the condition still exists on both sides” (Section I.B.13, Laterality)
- The FY 2027 ICD-10-CM Official Guidelines for Coding and Reporting were updated for the period October 1, 2026 to September 30, 2027.
“UPDATED October 1, 2026 (October 1, 2026 - September 30, 2027)” (Title page)
- The official guidelines say a code is invalid if it has not been coded to the full number of characters required for that code.
“A code is invalid if it has not been coded to the full number of characters required for that code” (Section I.B, Level of Detail in Coding)
- When a condition is bilateral and no bilateral code exists, the official guidelines say to assign separate codes for the left and the right side.
“If no bilateral code is provided and the condition is bilateral, assign separate codes for both the left and right side.” (Section I.B.13, Laterality)
- When the medical record does not identify the side, the official guidelines say to assign the code for the unspecified side.
“If the side is not identified in the medical record, assign the code for the unspecified side.” (Section I.B.13, Laterality)