ICD-10-CM 2027
ICD-10 code for Malassimilation
From the official ICD-10-CM alphabetic index entry “Malassimilation”. Page updated September 29, 2026.
About coding Malassimilation
The ICD-10-CM code for Malassimilation is K90.9 (Intestinal malabsorption, unspecified).
Within K90, choose K90.9 (unspecified) only when documentation doesn't support a more specific option: celiac disease (K90.0), tropical sprue (K90.1), blind loop syndrome, not elsewhere classified (K90.2), pancreatic steatorrhea (K90.3), other malabsorption due to intolerance (K90.4) and other intestinal malabsorption (K90.8).
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 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 Malassimilation ICD-10 codes
What is the ICD-10 code for Malassimilation?
- K90.9 — Intestinal malabsorption, unspecified.
Is K90.9 billable?
- Yes. K90.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K90.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K90.9 as a principal diagnosis.
Is K90.9 a CC or MCC?
- K90.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.