2026 ICD-10-CM Diagnosis Code T80.311AABO incompatibility with delayed hemolytic transfusion reaction, initial encounter

ICD-10-CM Codes›S00–T88›T80-T88›T80

ICD-10-CM T80.311A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T80.311A is a billable ICD-10-CM diagnosis code for ABO incompatibility with delayed hemolytic transfusion reaction, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 811 through 812. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.

Code Identity

ICD-10-CM Code
T80.311A
Billable Status
Yes — Valid for Submission
Code Describes
ABO incompatibility with delayed hemolytic transfusion reaction, initial encounter
Short Description
ABO incompatibility w delayed hemolytic transfs react, init
Parent Code
T80.311
ABO incompatibility with delayed hemolytic transfusion reaction

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT80-T88Complications of surgical and medical care, not elsewhere classified
CategoryT80Complications following infusion, transfusion and therapeutic injection
This CodeT80.311AABO incompatibility with delayed hemolytic transfusion reaction, initial encounter

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Complications following infusion, transfusion and therapeutic injection (T80). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR INJ037
Complication of other surgical or medical care, injury, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Blood Transfusion and Donation

Every year, millions of people in the United States receive life-saving blood transfusions. During a transfusion, you receive whole blood or parts of blood such as:

Read the full article at MedlinePlus

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

Convert T80.311A to ICD-9-CMHistory

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

ICD-9-CM
999.63 Abo incompat/delay HTR
Approximate The match is approximate rather than exact.

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 T80.311AOverview

Is T80.311A a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report ABO incompatibility with delayed hemolytic transfusion reaction, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T80.311A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for ABO incompatibility with delayed hemolytic transfusion reaction, such as an emergency visit or first evaluation.

What MS-DRG does T80.311A group to?

When ABO incompatibility with delayed hemolytic transfusion reaction, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of T80.311A?

Under the General Equivalence Mappings, ABO incompatibility with delayed hemolytic transfusion reaction, initial encounter converts to ICD-9-CM 999.63 (abo incompat/delay HTR). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.