2026 ICD-10-CM Diagnosis Code K90.1Tropical sprue

ICD-10-CM Codes›K00–K95›K90-K95›K90

ICD-10-CM K90.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

K90.1 is a billable ICD-10-CM diagnosis code for tropical sprue. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 391 through 392. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 14 closely related codes. Coders also document this condition as megaloblastic anemia due to disease of small intestine. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified gastrointestinal disorders.

K90.1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 66 for payment year 2026.

Code Identity

ICD-10-CM Code
K90.1
Billable Status
Yes — Valid for Submission
Code Describes
Tropical sprue
Short Description
Tropical sprue
Same as the full description in the CMS dataset.
Parent Code
K90
Intestinal malabsorption

Code Classification

ChapterK00–K95Diseases of the digestive system
SectionK90-K95Other diseases of the digestive system
CategoryK90Intestinal malabsorption
This CodeK90.1Tropical sprue

Medicare Risk Adjustment (HCC)Billing

K90.1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 66 — Pancreatic Disorders and Intestinal Malabsorption, Except Pancreatitis
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Megaloblastic anemia due to disease of small intestine
  • Megaloblastic anemia due to impaired absorption of folate
  • Megaloblastic anemia due to tropical sprue
  • Sprue
  • Tropical sprue

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Sprue NOS
  • Tropical steatorrhea

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR DIG025
Other specified and unspecified gastrointestinal disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Malabsorption Syndromes

Your small intestine does most of the digesting of the foods you eat. If you have a malabsorption syndrome, your small intestine cannot absorb nutrients from foods.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert K90.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
579.1 Tropical sprue
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About K90.1Overview

What is the ICD-10 code for tropical sprue?

The ICD-10-CM code for tropical sprue is K90.1 (sometimes written as K901). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is K90.1 (Intestinal malabsorption) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report tropical sprue on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does K90.1 group to?

When tropical sprue is the principal diagnosis on an inpatient stay, it groups to MS-DRG 391, 392, with relative weights from 0.7796 to 1.2683 depending on complications. Higher weights mean higher Medicare reimbursement.

Is K90.1 a CC or MCC?

CMS lists K90.1 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 14 closely related codes in its exclusion list.

What is the ICD-9 equivalent of K90.1?

Under the General Equivalence Mappings, tropical sprue converts to ICD-9-CM 579.1 (tropical sprue). The mapping is a direct match.

Does K90.1 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: K90.1 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 66 (Pancreatic Disorders and Intestinal Malabsorption, Except Pancreatitis).