ICD-10-CM 2027
ICD-10 code for Flush syndrome
From the official ICD-10-CM alphabetic index entry “Flush syndrome”. Page updated September 29, 2026.
About coding Flush syndrome
The ICD-10-CM code for Flush syndrome is E34.09 (Other carcinoid syndrome).
Within E34.0, choose E34.09 (Other carcinoid syndrome) only when documentation doesn't support a more specific option: unspecified (E34.00) and carcinoid heart syndrome (E34.01).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 643 (Endocrine Disorders with MCC, relative weight 1.6139), DRG 644 (Endocrine Disorders with CC, relative weight 1.0044) and DRG 645 (Endocrine Disorders without CC/MCC, relative weight 0.7459), in MDC 10 (Endocrine, Nutritional and Metabolic Diseases and Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Flush syndrome ICD-10 codes
What is the ICD-10 code for Flush syndrome?
- E34.09 — Other carcinoid syndrome.
Is E34.09 billable?
- Yes. E34.09 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E34.09 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E34.09 as a principal diagnosis.
Is E34.09 a CC or MCC?
- E34.09 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.