ICD-10-CM 2027
ICD-10 code for tryptophan metabolism disorder
From the official ICD-10-CM alphabetic index entry “Disorder (of) › tryptophan metabolism”. Page updated September 29, 2026.
About coding tryptophan metabolism disorder
The ICD-10-CM code for tryptophan metabolism disorder is E70.5 (Disorders of tryptophan metabolism).
Within E70 (disorders of aromatic amino-acid metabolism), E70.5 is specifically for disorders of tryptophan metabolism. Related codes cover classical phenylketonuria (E70.0), other hyperphenylalaninemias (E70.1), disorders of tyrosine metabolism (E70.2), albinism (E70.3), disorders of histidine metabolism (E70.4), other disorders of aromatic amino-acid metabolism (E70.8) and disorder of aromatic amino-acid metabolism, unspecified (E70.9).
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.
Common questions about tryptophan metabolism disorder ICD-10 codes
What is the ICD-10 code for tryptophan metabolism disorder?
- E70.5 — Disorders of tryptophan metabolism.
Is E70.5 billable?
- Yes. E70.5 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E70.5 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E70.5 as a principal diagnosis.
Is E70.5 a CC or MCC?
- E70.5 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.