Five coding principles

Five rules for every encounter

Five rules apply to every encounter. They come straight from WHO's morbidity coding and documentation guidance.

Main condition, then the others

Rule one. The main condition is the one condition determined to be the reason for admission, established at the end of the episode of care. Rule two. Code the other conditions that coexist or develop and affect the management of the patient. Conditions from an earlier episode with no bearing are left out.

• Step 1 · Main condition · Reason for admission. The one condition determined to be the reason for admission, established at the end of the episode of care.
• Step 2 · Other conditions · Affect management. Conditions that coexist or develop and affect the patient's management. Earlier-episode conditions with no bearing are left out.

Be as specific as the record allows

Rule three. Be as specific as the record allows. A diagnostic statement should be as informative as possible, so the code captures its detail. Choose unspecified only when the information isn't available. Choose other when the documentation is specific, but no category exists.

• Step 1 · Specificity · Full detail. A diagnostic statement should be as informative as possible, so the code captures its detail.
• Step 2 · Unspecified · Z. Only when the information is not available in the documentation.
• Step 3 · Other specified · Y. When the documentation is specific but no category exists: the closest match.

Postcoordinate, then verify

Rule four. Use postcoordination to describe one documented concept in full, never to rebuild a code that already exists. Rule five. Verify the result in the tabular list, for exclusions, inclusions and notes, at category, grouping and chapter level.

• Step 1 · Postcoordinate · One concept. Combine stem and extension codes to describe one documented concept in full, never to rebuild a code that already exists.
• Step 2 · Verify · Tabular list. Check exclusions, inclusions and notes at the level of the category, its grouping and the chapter.

If it isn't established

One caution, with two different rules. The clinician should document the symptom, abnormal finding or problem rather than possible or suspected. But if a coder meets a main condition recorded as suspected, with nothing further to clarify it, the coder codes it as if established. And a ruled-out condition is the main condition only when no treatment or follow-up was needed.

• The clinician · Symptom · If no definite diagnosis is established, document the symptom or finding, not “possible” or “suspected”.
• The coder · Established · If the main condition is recorded as suspected and nothing clarifies it, code it as if established.
• Ruled out · Exception · A ruled-out condition is the main condition only when no treatment or follow-up was needed.

Check yourself

Pause and think. In ICD-11, how is the main diagnosis for morbidity defined? The answer: The reason for admission, after assessment at the end of the stay. WHO's table of changes states the main diagnosis is the reason for admission, after assessment at the end of the stay.

• The most resource-intensive condition
• The first condition recorded on the chart
• The reason for admission, after assessment at the end of the stay
• The most severe condition regardless of admission

Keep these in mind

Main condition, the reason for admission. Other conditions that affect management. As specific as the record allows. And postcoordinate one documented concept, then verify the result.

• Main condition: the reason for admission
• Other conditions that affect management
• As specific as the record allows
• Postcoordinate one concept, then verify