ICD-10-CM 2027
ICD-10 code for lactose malabsorption
From the official ICD-10-CM alphabetic index entry “Malabsorption › lactose”. Page updated September 29, 2026.
About coding lactose malabsorption
The ICD-10-CM code for lactose malabsorption is E73.9 (Lactose intolerance, unspecified).
Within E73, choose E73.9 (unspecified) only when documentation doesn't support a more specific option: congenital lactase deficiency (E73.0), secondary lactase deficiency (E73.1) and other lactose intolerance (E73.8).
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 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), 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 lactose malabsorption ICD-10 codes
What is the ICD-10 code for lactose malabsorption?
- E73.9 — Lactose intolerance, unspecified.
Is E73.9 billable?
- Yes. E73.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can E73.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict E73.9 as a principal diagnosis.
Is E73.9 a CC or MCC?
- No. E73.9 is neither a CC nor an MCC under MS-DRG v44.0.