2026 ICD-10-CM Diagnosis Code M31.10Thrombotic microangiopathy, unspecified
ICD-10-CM Codes›M00–M99›M30-M36›M31
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Risk Adjusts — HCC 112
- Chronic Condition
M31.10 is a billable ICD-10-CM diagnosis code for thrombotic microangiopathy, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 545 through 547. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 25 closely related codes. Coders also document this condition as acute intravascular thrombotic microangiopathy. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Systemic lupus erythematosus and connective tissue disorders and Vasculitis.
For Medicare Advantage risk adjustment, M31.10 maps to CMS-HCC Category 112 (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions) under the V28 model, adding a risk factor of about 0.450 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
M31.10 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
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.
- Acute intravascular thrombotic microangiopathy
- Chronic thrombotic microangiopathy
- Thrombotic microangiopathy
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.
Code History & ChangesHistory
Replacement M31.10 replaces the following previously assigned code(s):
- M31.1 - Thrombotic microangiopathy
Questions About M31.10Overview
What is the ICD-10 code for thrombotic microangiopathy, unspecified?
The ICD-10-CM code for thrombotic microangiopathy, unspecified is M31.10 (sometimes written as M3110). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is M31.10 (Thrombotic microangiopathy) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report thrombotic microangiopathy, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does M31.10 group to?
When thrombotic microangiopathy, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 545, 546, 547, with relative weights from 0.8362 to 2.4817 depending on complications. Higher weights mean higher Medicare reimbursement.
Is M31.10 a CC or MCC?
CMS lists M31.10 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 25 closely related codes in its exclusion list.
What HCC is M31.10?
M31.10 (thrombotic microangiopathy, unspecified) maps to CMS-HCC Category 112 (Immune Thrombocytopenia and Specified Coagulation Defects and Hemorrhagic Conditions), commonly written as HCC 112, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 40 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 84.
Does M31.10 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, M31.10 adds a risk adjustment factor of about 0.450 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.450 to 0.708 depending on the payment segment). A more severe related category (HCC 111) supersedes it when both are reported. See the full factor table on the HCC 112 category page.
