2022 ICD-10-CM Diagnosis Code B27.9

Infectious mononucleosis, unspecified

    2016 2017 2018 2019 2020 2021 2022 Non-Billable/Non-Specific Code
  • B27.9 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
  • The 2022 edition of ICD-10-CM B27.9 became effective on October 1, 2021.
  • This is the American ICD-10-CM version of B27.9 - other international versions of ICD-10 B27.9 may differ.
The following code(s) above B27.9 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to B27.9:
  • A00-B99
    2022 ICD-10-CM Range A00-B99

    Certain infectious and parasitic diseases

    • diseases generally recognized as communicable or transmissible
    Type 1 Excludes
    • certain localized infections - see body system-related chapters
    Type 2 Excludes
    • carrier or suspected carrier of infectious disease (Z22.-)
    • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
    • infectious and parasitic diseases specific to the perinatal period (P35-P39)
    • influenza and other acute respiratory infections (J00-J22)
    Use Additional
    • code to identify resistance to antimicrobial drugs (Z16.-)
    Certain infectious and parasitic diseases
  • B27
    ICD-10-CM Diagnosis Code B27

    Infectious mononucleosis

      2016 2017 2018 2019 2020 2021 2022 Non-Billable/Non-Specific Code
    • glandular fever
    • monocytic angina
    • Pfeiffer's disease
    Infectious mononucleosis
Clinical Information
  • A common, acute infection usually caused by the epstein-barr virus (herpesvirus 4, human). There is an increase in mononuclear white blood cells and other atypical lymphocytes, generalized lymphadenopathy, splenomegaly, and occasionally hepatomegaly with hepatitis.
  • Acute disease characterized by fever and swollen lymph nodes and an abnormal increase of mononuclear leucocytes or monocytes in the bloodstream; not highly contagious; some believe it can be transmitted by kissing.
  • Infectious mononucleosis, or "mono", is an infection caused by the epstein-barr virus. The virus spreads through saliva, which is why it's sometimes called "kissing disease." mono occurs most often in 15 to 17-year-olds. However, you can get it at any age. Symptoms of mono include
    • fever
    • sore throat
    • swollen lymph glands
    sometimes you may also have a swollen spleen. Serious problems are rare. A blood test can show if you have mono. Most people get better in two to four weeks. However, you may feel tired for a few months afterward. Treatment focuses on helping symptoms and includes medicines for pain and fever, warm salt water gargles and plenty of rest and fluids.
Code History
  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
Code annotations containing back-references to B27.9:
  • Code First: K77
    ICD-10-CM Diagnosis Code K77

    Liver disorders in diseases classified elsewhere

      2016 2017 2018 2019 2020 2021 2022 Billable/Specific Code Manifestation Code
    Code First
    Type 1 Excludes
    • alcoholic hepatitis (K70.1-)
    • alcoholic liver disease (K70.-)
    • cytomegaloviral hepatitis (B25.1)
    • herpesviral [herpes simplex] hepatitis (B00.81)
    • mumps hepatitis (B26.81)
    • sarcoidosis with liver disease (D86.89)
    • secondary syphilis with liver disease (A51.45)
    • syphilis (late) with liver disease (A52.74)
    • toxoplasmosis (acquired) hepatitis (B58.1)
    • tuberculosis with liver disease (A18.83)
  • Type 1 Excludes: G63
    ICD-10-CM Diagnosis Code G63

    Polyneuropathy in diseases classified elsewhere

      2016 2017 2018 2019 2020 2021 2022 Billable/Specific Code Manifestation Code
    Code First
    Type 1 Excludes
    • polyneuropathy (in):
    • diabetes mellitus (E08-E13 with .42)
    • diphtheria (A36.83)
    • infectious mononucleosis complicated by polyneuropathy (B27.0-B27.9 with fifth character 1)
    • Lyme disease (A69.22)
    • mumps (B26.84)
    • postherpetic (B02.23)
    • rheumatoid arthritis (M05.5-)
    • scleroderma (M34.83)
    • systemic lupus erythematosus (M32.19)
ICD-10-CM Codes Adjacent To B27.9
B27.1 Cytomegaloviral mononucleosis
B27.10 …… without complications
B27.11 …… with polyneuropathy
B27.12 …… with meningitis
B27.19 …… with other complication
B27.8 Other infectious mononucleosis
B27.80 …… without complication
B27.81 …… with polyneuropathy
B27.82 …… with meningitis
B27.89 …… with other complication
B27.9 Infectious mononucleosis, unspecified
B27.90 …… without complication
B27.91 …… with polyneuropathy
B27.92 …… with meningitis
B27.99 …… with other complication
B30 Viral conjunctivitis
B30.0 Keratoconjunctivitis due to adenovirus
B30.1 Conjunctivitis due to adenovirus
B30.2 Viral pharyngoconjunctivitis
B30.3 Acute epidemic hemorrhagic conjunctivitis (enteroviral)
B30.8 Other viral conjunctivitis

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.