2024 ICD-10-CM Diagnosis Code T78.40XS

Allergy, unspecified, sequela

ICD-10-CM Code:
T78.40XS
ICD-10 Code for:
Allergy, unspecified, sequela
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    (S00–T88)
    • Other and unspecified effects of external causes
      (T66-T78)
      • Adverse effects, not elsewhere classified
        (T78)

T78.40XS is a billable diagnosis code used to specify a medical diagnosis of allergy, unspecified, sequela. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

T78.40XS is a sequela code, includes a 7th character and should be used for complications that arise as a direct result of a condition like allergy unspecified. According to ICD-10-CM Guidelines a "sequela" code should be used for chronic or residual conditions that are complications of an initial acute disease, illness or injury. The most common sequela is pain. Usually, two diagnosis codes are needed when reporting sequela. The first code describes the nature of the sequela while the second code describes the sequela or late effect.

Unspecified diagnosis codes like T78.40XS are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Acute allergic reaction
  • Adverse cutaneous reaction to diagnostic procedure
  • Adverse reaction caused by detergent
  • Adverse reaction to bone resorption inhibitor
  • Adverse reaction to oil
  • Allergic bronchitis
  • Allergic condition
  • Allergic cough
  • Allergic disorder
  • Allergic disorder - symptom change
  • Allergic disorder monitoring status
  • Allergic disorder of digestive system
  • Allergic disorder of respiratory system
  • Allergic disorder of respiratory tract
  • Allergic disorder treatment started
  • Allergic disposition
  • Allergic encephalitis
  • Allergic facies
  • Allergic gingival disease
  • Allergic otitis externa
  • Allergic reaction
  • Allergic reaction after allergen immunotherapy
  • Allergic reaction caused by analgesic
  • Allergic reaction caused by anesthetic
  • Allergic reaction caused by Hevea brasiliensis latex protein
  • Allergic reaction caused by hymenoptera venom
  • Allergic reaction caused by hymenoptera venom
  • Allergic reaction caused by insect bite and/or insect sting
  • Allergic reaction caused by insect bite and/or insect sting
  • Allergic reaction caused by insect bite and/or insect sting
  • Allergic reaction due to allergy skin test
  • Allergic reaction to adhesive
  • Allergic reaction to bee sting
  • Allergic reaction to colophony
  • Allergic reaction to detergent
  • Allergic reaction to drug
  • Allergic reaction to hair dye
  • Allergic reaction to nickel
  • Allergic reaction to oil
  • Allergic reaction to platinum
  • Allergic reaction to venom
  • Allergic reaction to wasp sting
  • Allergic sensitization
  • Allergic vaginitis
  • Allergy skin test positive
  • Allergy test positive
  • Allergy treatment changed
  • Allopurinol adverse reaction
  • Allopurinol hypersensitivity syndrome
  • Angry back syndrome
  • Atopic reaction
  • Cell-mediated immune reaction
  • Chronic allergic otitis externa
  • Chronic non-infective otitis externa
  • Complication of diagnostic procedure
  • Complication of patch testing
  • Contact hypersensitivity reaction
  • Contact hypersensitivity reaction
  • Cutaneous hypersensitivity
  • Cutaneous hypersensitivity reaction caused by Hymenoptera venom
  • Cutis laxa following hypersensitivity reaction
  • Cutis laxa, acquired type
  • Drug reaction with eosinophilia and systemic symptoms
  • Drug reaction with eosinophilia and systemic symptoms
  • Drug reaction with eosinophilia and systemic symptoms
  • Drug reaction with eosinophilia and systemic symptoms caused by strontium ranelate
  • Emollient adverse reaction
  • Hypersensitivity condition
  • Hypersensitivity disorder of respiratory tract
  • Hypersensitivity disposition
  • Hypersensitivity finding
  • Hypersensitivity finding
  • Hypersensitivity finding
  • Hypersensitivity gingivitis
  • Hypersensitivity reaction
  • Hypersensitivity reaction mediated by antibody
  • Hypersensitivity reaction mediated by immune complex
  • Hypersensitivity reaction with blocking antibody
  • Hypersensitivity reaction without blocking antibody
  • Immune hypersensitivity reaction by mechanism
  • Injection site hypersensitivity
  • Laryngotracheobronchitis
  • Late effect of accidental injury
  • Late effect of accidental injury
  • Myocarditis due to hypersensitivity state
  • Non-allergic hypersensitivity condition
  • Pain provoked by allergen
  • Recurrent allergic croup
  • Recurrent croup
  • Skin: type 3 delayed reaction
  • Type 1 hypersensitivity response
  • Type 1 skin hypersensitivity reaction
  • Type 4 hypersensitivity response
  • Ulcer of esophagus due to allergic disorder
  • Xanthine oxidase inhibitor adverse reaction

Clinical Classification

Coding Guidelines

The appropriate 7th character is to be added to each code from block Adverse effects, not elsewhere classified (T78). Use the following options for the aplicable episode of care:

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

Present on Admission (POA)

T78.40XS is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here.

CMS POA Indicator Options and Definitions

POA IndicatorReason for CodeCMS will pay the CC/MCC DRG?
YDiagnosis was present at time of inpatient admission.YES
NDiagnosis was not present at time of inpatient admission.NO
UDocumentation insufficient to determine if the condition was present at the time of inpatient admission.NO
WClinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.YES
1Unreported/Not used - Exempt from POA reporting. NO

Convert T78.40XS to ICD-9-CM

  • ICD-9-CM Code: 909.9 - Late eff exter cause NEC
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Patient Education


Allergy

An allergy is a reaction by your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are:

  • Pollen
  • Dust mites
  • Mold spores
  • Pet dander
  • Food
  • Insect stings
  • Medicines

Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Genes and the environment probably both play a role.

Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe. Anaphylaxis is a severe reaction that can be life-threatening. Doctors use skin and blood tests to diagnose allergies. Treatments include medicines, allergy shots, and avoiding the substances that cause the reactions.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

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.