ICD-10-CM 2027
ICD-10 code for histidine metabolism disorder
Disorders of histidine metabolism, unspecified
From the official ICD-10-CM alphabetic index entry “Disorder (of) › histidine metabolism”. Page updated September 29, 2026.
About coding histidine metabolism disorder
The ICD-10-CM code for histidine metabolism disorder is E70.40 (Disorders of histidine metabolism, unspecified). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on E70.40.
Within E70.4, choose E70.40 (unspecified) only when documentation doesn't support a more specific option: Histidinemia (E70.41) and other disorders of histidine metabolism (E70.49).
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 642 (Inborn and Other Disorders of Metabolism, relative weight 1.3219), 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.
More specific histidine metabolism disorder codes (official index)
Common questions about histidine metabolism disorder ICD-10 codes
What is the ICD-10 code for histidine metabolism disorder?
- E70.40 — Disorders of histidine metabolism, unspecified. More specific codes apply when the documentation supports them: E70.41, E70.49.
What is the ICD-10 code for histidinemia histidine metabolism disorder?
- E70.41 — Histidinemia.
What is the ICD-10 code for other specified histidine metabolism disorder?
- E70.49 — Other disorders of histidine metabolism.
Is E70.40 billable?
- Yes. E70.40 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E70.40 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E70.40 as a principal diagnosis.
Is E70.40 a CC or MCC?
- E70.40 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.