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M84.378K vs M84.379K

M84.378K (Stress fracture, left toe(s), subsequent encounter for fracture with nonunion) compared with M84.379K (Stress fracture, unspecified toe(s), subsequent encounter for fracture with nonunion), from the official CMS tabular data. M84.378K and M84.379K code the same condition on opposite sides.

Relationship

Review

Laterality relationship

M84.378K
Left
Stress fracture, left toe(s), subsequent encounter for fracture with nonunion
M84.379K
Unspecified
Stress fracture, unspecified toe(s), subsequent encounter for fracture with nonunion

Same condition; these differ only in which side is documented.

These codes share a category and title and differ only in the side affected. The documentation decides which applies, and a bilateral code is reported only where the code set provides one.

Source: ICD-10-CM tabular list (laterality variant derived from the code title)

Can these codes be reported together?

Same condition, opposite side. M84.378K and M84.379K name the same condition on opposite sides of the body.

Same category and title, differing only in which side is affected — the documentation decides which one applies, and a bilateral code is reported only where the code set provides one.

Side by side

M84.378KStress fracture, left toe(s), subsequent encounter for fracture with nonunionM84.379KStress fracture, unspecified toe(s), subsequent encounter for fracture with nonunion
Billing statusBillableBillable
ClassificationM00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)M00-M99 — Diseases of the Musculoskeletal System and Connective Tissue (M00-M99)
DefinitionStress fracture, left toe(s), subsequent encounter for fracture with nonunion is a billable ICD-10-CM diagnosis code (M84.378K).Stress fracture, unspecified toe(s), subsequent encounter for fracture with nonunion is a billable ICD-10-CM diagnosis code (M84.379K).
7th characterThe appropriate 7th character is to be added to each code from subcategory M84.3:The appropriate 7th character is to be added to each code from subcategory M84.3:
Use additional code
external cause code(s) to identify the cause of the stress fracture
external cause code(s) to identify the cause of the stress fracture

Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources