ICD-10-CM Code A36.9

Diphtheria, unspecified

Version 2021 Billable Code

Valid for Submission

A36.9 is a billable code used to specify a medical diagnosis of diphtheria, unspecified. The code is valid for the fiscal year 2021 for the submission of HIPAA-covered transactions. The ICD-10-CM code A36.9 might also be used to specify conditions or terms like diphtheria due to corynebacterium diphtheriae or diphtheria like disorder due to corynebacterium ulcerans or infection due to corynebacterium diphtheriae.

Short Description:Diphtheria, unspecified
Long Description:Diphtheria, unspecified

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code A36.9 are found in the index:


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

  • Diphtheria due to Corynebacterium diphtheriae
  • Diphtheria like disorder due to Corynebacterium ulcerans
  • Infection due to Corynebacterium diphtheriae

Clinical Information

  • DIPHTHERIA-. a localized infection of mucous membranes or skin caused by toxigenic strains of corynebacterium diphtheriae. it is characterized by the presence of a pseudomembrane at the site of infection. diphtheria toxin produced by c. diphtheriae can cause myocarditis polyneuritis and other systemic toxic effects.
  • DIPHTHERIA ANTITOXIN-. an antitoxin produced against the toxin of corynebacterium diphtheriae that is used for the treatment of diphtheria.
  • DIPHTHERIA TOXIN-. an adp ribosylating polypeptide produced by corynebacterium diphtheriae that causes the signs and symptoms of diphtheria. it can be broken into two unequal domains: the smaller catalytic a domain is the lethal moiety and contains monoadp ribose transferases which transfers adp ribose to peptide elongation factor 2 thereby inhibiting protein synthesis; and the larger b domain that is needed for entry into cells.
  • DIPHTHERIA TOXOID-. the formaldehyde inactivated toxin of corynebacterium diphtheriae. it is generally used in mixtures with tetanus toxoid and pertussis vaccine; dtp; or with tetanus toxoid alone dt for pediatric use and td which contains 5 to 10 fold less diphtheria toxoid for other use. diphtheria toxoid is used for the prevention of diphtheria; diphtheria antitoxin is for treatment.
  • FOWLPOX-. a poxvirus infection of poultry and other birds characterized by the formation of wart like nodules on the skin and diphtheritic necrotic masses cankers in the upper digestive and respiratory tracts.
  • DIPHTHERIA TETANUS PERTUSSIS VACCINE-. a vaccine consisting of diphtheria toxoid; tetanus toxoid; and whole cell pertussis vaccine. the vaccine protects against diphtheria tetanus and whooping cough.
  • DIPHTHERIA TETANUS VACCINE-. a combined vaccine used to prevent infection with diphtheria and tetanus toxoid. this is used in place of dtp vaccine diphtheria tetanus pertussis vaccine when pertussis vaccine is contraindicated.
  • DIPHTHERIA TETANUS ACELLULAR PERTUSSIS VACCINES-. combined vaccines consisting of diphtheria toxoid; tetanus toxoid; and an acellular form of pertussis vaccine. at least five different purified antigens of b. pertussis have been used in various combinations in these vaccines.
  • HEPARIN BINDING EGF LIKE GROWTH FACTOR-. an egf family member that is expressed in a variety of hematopoietic endothelial vascular smooth muscle and epithelial cells. it is synthesized as a transmembrane protein which is cleaved by proteases to produce the secreted form of the protein which has specificity for the egf receptor and the erbb 4 receptor. the membrane bound form of the protein has been identified as the receptor which binds to and allows diphtheria toxin to enter cells.

Diagnostic Related Groups

The ICD-10 code A36.9 is grouped in the following groups for version MS-DRG V38.0 What are Diagnostic Related Groups?
The Diagnostic Related Groups (DRGs) are a patient classification scheme which provides a means of relating the type of patients a hospital treats. The DRGs divides all possible principal diagnoses into mutually exclusive principal diagnosis areas referred to as Major Diagnostic Categories (MDC).
applicable from 10/01/2020 through 09/30/2021.


Convert A36.9 to ICD-9

Code Classification

  • Certain infectious and parasitic diseases (A00–B99)
    • Other bacterial diseases (A30-A49)
      • Diphtheria (A36)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients


Diphtheria is a serious bacterial infection. You can catch it from a person who has the infection and coughs or sneezes. You can also get infected by coming in contact with an object, such as a toy, that has bacteria on it.

Diphtheria usually affects the nose and throat. Symptoms include

  • Sore throat
  • Swollen glands in the neck
  • Fever
  • Weakness

Your doctor will diagnose it based on your signs and symptoms and a lab test. Getting treatment for diphtheria quickly is important. If your doctor suspects that you have it, you'll start treatment before the lab tests come back. Treatment is with antibiotics.

The diphtheria, pertussis, and tetanus vaccine can prevent diphtheria, but its protection does not last forever. Children need another dose, or booster, at about age 12. Then, as adults, they should get a booster every 10 years. Diphtheria is very rare in the United States because of the vaccine.

Centers for Disease Control and Prevention

  • Diphtheria (Medical Encyclopedia)

[Learn More]