2026 ICD-10-CM Diagnosis Code T80.910AAcute hemolytic transfusion reaction, unspecified incompatibility, initial encounter
ICD-10-CM Codes›S00–T88›T80-T88›T80
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- 7th Character A — Initial Encounter
- Not Chronic
T80.910A is a billable ICD-10-CM diagnosis code for acute hemolytic transfusion reaction, unspecified incompatibility, 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 791, 793, 811 through 812. 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 20 closely related codes. Coders also document this condition as hemolytic transfusion reaction. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Complication of other surgical or medical care, injury, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Hemolytic transfusion reaction
- Immediate hemolytic transfusion reaction
- Immediate transfusion reaction
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.
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 T80.910A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T80.910AOverview
Is T80.910A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute hemolytic transfusion reaction, unspecified incompatibility, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T80.910A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for acute hemolytic transfusion reaction, unspecified incompatibility, such as an emergency visit or first evaluation.
What MS-DRG does T80.910A group to?
When acute hemolytic transfusion reaction, unspecified incompatibility, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 791, 793, 811, 812, with relative weights from 0.9182 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T80.910A a CC or MCC?
CMS lists T80.910A 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 20 closely related codes in its exclusion list.
What is the ICD-9 equivalent of T80.910A?
Under the General Equivalence Mappings, acute hemolytic transfusion reaction, unspecified incompatibility, initial encounter converts to ICD-9-CM 999.84 (acute HTR NOS). The mapping is approximate, so confirm the match fits the documentation.
