ICD-10 to ICD-11 mapping: crosswalks

Same condition, different revision

The same condition, recorded in a different revision. A crosswalk lets data from one revision be read in another.

Forward and backward

A crosswalk finds equivalent codes in two revisions. A forward crosswalk maps codes from an earlier classification to the later one, to group old data with new software and to compare over time. A backward crosswalk maps current codes back to earlier ones, for earlier groupers or for time series.

Historical and logical

There are two kinds of map. A historical crosswalk selects the map that gives the most appropriate coding and clinical meaning, and it may consist of one or more codes. A logical, or special-purpose, crosswalk relates each code to the most clinically similar code that achieves the right DRG assignment.

Mapped data is not identical

There's a catch. Crosswalks lose some information because precision differs between revisions. Malignant neoplasm of breast is classified in ICD-10 by site only, and in ICD-11 by site and histopathology. So data mapped from ICD-10 will not be exactly equivalent to data first reported in ICD-10.

• 0 · 0 · partial
• 0 · 1 · partial

Code the same episodes twice

Dual coding studies code the same episodes in two ICD versions and compare the results. They show coding variations, and the effect on workforce, revenue, trend series and casemix grouping. For mortality they are easier. For morbidity they are less simple, but possible.

• What · Two versions · Coding the same episodes in two ICD versions and comparing the results.
• Why · Impact · Shows coding variations and the effect on workforce, revenue, trend series and casemix grouping.

Check yourself

Pause and think. A forward crosswalk: The answer: Maps codes from an earlier classification to a later one. A forward crosswalk uses codes from an earlier classification to map to corresponding codes in a later one.

• Maps codes from a later classification back to an earlier one
• Maps codes from an earlier classification to a later one
• Translates codes between languages
• Combines two stem codes

Keep these in mind

A crosswalk finds equivalent codes across revisions. It can run forward or backward, and be historical or logical. Mapped data is not exactly equivalent. And dual coding studies measure the difference.

• A crosswalk finds equivalent codes across revisions
• Forward and backward; historical and logical
• Mapped data is not exactly equivalent
• Dual coding studies measure the difference