2027 ICD-10-CM Diagnosis Code T50.A15SAdverse effect of pertussis vaccine, including combinations with a pertussis component, sequela

ICD-10-CM T50.A15S

CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

T50.A15S is a billable ICD-10-CM diagnosis code for adverse effect of pertussis vaccine, including combinations with a pertussis component, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 922 through 923. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.

Code Identity

ICD-10-CM Code

T50.A15S

Billable Status

Yes — Valid for Submission

Code Describes

Adverse effect of pertussis vaccine, including combinations with a pertussis component, sequela

Short Description

Advrs effect of pertuss vaccine, inc combin w pertuss, sqla

Parent Code

T50.A15

Adverse effect of pertussis vaccine, including combinations with a pertussis component

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes

SectionT36-T50Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances

CategoryT50Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances

This CodeT50.A15SAdverse effect of pertussis vaccine, including combinations with a pertussis component, sequela

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T50.A15S.

Unacceptable principal diagnosis

There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

T50.A15S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances (T36-T50).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

Adverse reaction to component of vaccine product containing low dose acellular Bordetella pertussis and Clostridium tetani and low dose Corynebacterium diphtheriae antigens
Adverse reaction to component of vaccine product containing only acellular Bordetella pertussis and Clostridium tetani and Corynebacterium diphtheriae antigens
Adverse reaction to diphtheria and acellular pertussis and Haemophilus influenzae type b and hepatitis B and inactivated poliomyelitis and tetanus vaccine
Adverse reaction to diphtheria, pertussis, and tetanus vaccine
Adverse reaction to Haemophilus influenzae type b vaccine
Adverse reaction to hepatitis B vaccine
Adverse reaction to pertussis vaccine
Adverse reaction to poliomyelitis vaccine
Anaphylaxis caused by component of vaccine product containing low dose acellular Bordetella pertussis and Clostridium tetani and low dose Corynebacterium diphtheriae antigens
Anaphylaxis caused by component of vaccine product containing only acellular Bordetella pertussis and Clostridium tetani and Corynebacterium diphtheriae antigens
Encephalitis caused by pertussis vaccine

Coding GuidelinesGuidance

When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.

The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances (T50). 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 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to T50.A15S: its own notes plus those printed at T50, block T36-T50, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.