ICD-10-CM 2027
ICD-10 code for Ergosterol deficiency
From the official ICD-10-CM alphabetic index entry “Deficiency, deficient › ergosterol”. Page updated September 29, 2026.
About coding Ergosterol deficiency
The ICD-10-CM code for Ergosterol deficiency is E55.9 (Vitamin D deficiency, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on E55.9.
Within E55, choose E55.9 (unspecified) only when documentation doesn't support a more specific option: rickets, active (E55.0).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 640 (Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes with MCC, relative weight 1.3395) and DRG 641 (Miscellaneous Disorders of Nutrition, Metabolism, Fluids and Electrolytes without MCC, relative weight 0.7865), 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 Ergosterol deficiency codes (official index)
- with
- adult osteomalacia M83.8 — Other adult osteomalacia
- rickets
Common questions about Ergosterol deficiency ICD-10 codes
What is the ICD-10 code for Ergosterol deficiency?
- E55.9 — Vitamin D deficiency, unspecified. More specific codes apply when the documentation supports them: M83.8.
Is E55.9 billable?
- Yes. E55.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E55.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E55.9 as a principal diagnosis.
Is E55.9 a CC or MCC?
- No. E55.9 is neither a CC nor an MCC under MS-DRG v44.0.