ICD-10-CM 2027
ICD-10 code for Cryptogenic stroke
From the official ICD-10-CM alphabetic index entry “Stroke (apoplectic) (brain) (ischemic) (paralytic) › cryptogenic”. Page updated September 29, 2026.
About coding Cryptogenic stroke
The ICD-10-CM code for Cryptogenic stroke is I63.9 (Cerebral infarction, unspecified).
Within I63, choose I63.9 (unspecified) only when documentation doesn't support a more specific option: due to thrombosis of precerebral arteries (I63.0), due to embolism of precerebral arteries (I63.1), due to unspecified occlusion or stenosis of precerebral arteries (I63.2), due to thrombosis of cerebral arteries (I63.3), due to embolism of cerebral arteries (I63.4), due to unspecified occlusion or stenosis of cerebral arteries (I63.5), due to cerebral venous thrombosis, nonpyogenic (I63.6) and other cerebral infarction (I63.8).
The conditions in its Excludes2 note aren't part of I63.9, but may be coded alongside it if the patient has both: transient cerebral ischemic attacks and related syndromes (G45.-).
Use an additional code, if applicable, to identify status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82). Use an additional code, if known, to indicate National Institutes of Health Stroke Scale (NIHSS) score (R29.7-).
Common questions about Cryptogenic stroke ICD-10 codes
What is the ICD-10 code for Cryptogenic stroke?
- I63.9 — Cerebral infarction, unspecified.
Is I63.9 billable?
- Yes. I63.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can I63.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict I63.9 as a principal diagnosis.
Is I63.9 a CC or MCC?
- I63.9 is an MCC (major complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.