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  6. 2025 ICD-10-CM Code B27

2025 ICD-10-CM Diagnosis Code B27

Infectious mononucleosis

ICD-10-CM Code:
B27
ICD-10 Code for:
Infectious mononucleosis
Is Billable?
Not Valid for Submission
Code Navigator:

B27 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of infectious mononucleosis. The code is not specific and is NOT valid for the year 2025 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Infectious mononucleosis

Non-specific codes like B27 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for infectious mononucleosis:

  • B27.0 for Gammaherpesviral mononucleosis - NON-BILLABLE CODE

  • Use B27.00 for Gammaherpesviral mononucleosis without complication - BILLABLE CODE

  • Use B27.01 for Gammaherpesviral mononucleosis with polyneuropathy - BILLABLE CODE

  • Use B27.02 for Gammaherpesviral mononucleosis with meningitis - BILLABLE CODE

  • Use B27.09 for Gammaherpesviral mononucleosis with other complications - BILLABLE CODE

  • B27.1 for Cytomegaloviral mononucleosis - NON-BILLABLE CODE

  • Use B27.10 for Cytomegaloviral mononucleosis without complications - BILLABLE CODE

  • Use B27.11 for Cytomegaloviral mononucleosis with polyneuropathy - BILLABLE CODE

  • Use B27.12 for Cytomegaloviral mononucleosis with meningitis - BILLABLE CODE

  • Use B27.19 for Cytomegaloviral mononucleosis with other complication - BILLABLE CODE

  • B27.8 for Other infectious mononucleosis - NON-BILLABLE CODE

  • Use B27.80 for Other infectious mononucleosis without complication - BILLABLE CODE

  • Use B27.81 for Other infectious mononucleosis with polyneuropathy - BILLABLE CODE

  • Use B27.82 for Other infectious mononucleosis with meningitis - BILLABLE CODE

  • Use B27.89 for Other infectious mononucleosis with other complication - BILLABLE CODE

  • B27.9 for Infectious mononucleosis, unspecified - NON-BILLABLE CODE

  • Use B27.90 for Infectious mononucleosis, unspecified without complication - BILLABLE CODE

  • Use B27.91 for Infectious mononucleosis, unspecified with polyneuropathy - BILLABLE CODE

  • Use B27.92 for Infectious mononucleosis, unspecified with meningitis - BILLABLE CODE

  • Use B27.99 for Infectious mononucleosis, unspecified with other complication - BILLABLE CODE

Code Classification

  • Certain infectious and parasitic diseases
    A00–B99
    • Other viral diseases
      B25-B34
      • Infectious mononucleosis
        B27

Clinical Information

  • Fatigue Syndrome, Chronic

    a syndrome characterized by persistent or recurrent fatigue, diffuse musculoskeletal pain, sleep disturbances, and subjective cognitive impairment of 6 months duration or longer. symptoms are not caused by ongoing exertion; are not relieved by rest; and result in a substantial reduction of previous levels of occupational, educational, social, or personal activities. minor alterations of immune, neuroendocrine, and autonomic function may be associated with this syndrome. there is also considerable overlap between this condition and fibromyalgia. (from semin neurol 1998;18(2):237-42; ann intern med 1994 dec 15;121(12): 953-9)

  • Herpesvirus 4, Human

    the type species of lymphocryptovirus, subfamily gammaherpesvirinae, infecting b-cells in humans. it is thought to be the causative agent of infectious mononucleosis and is strongly associated with oral hairy leukoplakia (leukoplakia, hairy;), burkitt lymphoma; and other malignancies.

  • Infectious Mononucleosis

    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.

  • Fibromyalgia

    a common nonarticular rheumatic syndrome characterized by myalgia and multiple points of focal muscle tenderness to palpation (trigger points). muscle pain is typically aggravated by inactivity or exposure to cold. this condition is often associated with general symptoms, such as sleep disturbances, fatigue, stiffness, headaches, and occasionally depression. there is significant overlap between fibromyalgia and the chronic fatigue syndrome (fatigue syndrome, chronic). fibromyalgia may arise as a primary or secondary disease process. it is most frequent in females aged 20 to 50 years. (from adams et al., principles of neurology, 6th ed, p1494-95)

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.


Includes

Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
  • glandular fever
  • monocytic angina
  • Pfeiffer's disease

Patient Education


Infectious Mononucleosis

What is infectious mononucleosis (mono)?

Infectious mononucleosis (mono) is a disease caused by viruses.The most common cause is the Epstein-Barr virus (EBV). Mono is contagious, which means it can spread from person to person. It is common among teenagers and young adults, especially college students.

What causes infectious mononucleosis (mono)?

Mono can be caused by many different viruses. But it is most often caused by the Epstein-Barr virus (EBV). EBV is found all over the world. Most people get an EBV infection at some point in their lives, but only some of them will get the symptoms of mono. EBV infections often happen during childhood or when someone is a young adult. EBV infections in children usually do not cause symptoms. And when they do, it's hard to tell the difference between the symptoms of mono and the symptoms of other common childhood illnesses such as the flu. Teens and young adults who get EBV are more likely to have symptoms that are typical of mono.

EBV and the other viruses that cause mono are usually spread through body fluids, especially saliva (spit). This means that you can get it through kissing. That's why mono is sometimes called "the kissing disease." But you can also get these viruses if you share food, drinks, forks, spoons, or lip balm with someone who has mono. Other less common ways of getting an infection are through blood transfusions, organ transplants, and blood and semen during sexual contact.

What are the symptoms of infectious mononucleosis (mono)?

The symptoms of mono usually start four to six weeks after you get the infection. But they may start sooner in young children. The symptoms often develop slowly, and they may not all happen at the same time. They can include:

  • Extreme fatigue
  • Fever
  • Sore throat
  • Head and body aches
  • Swollen lymph glands in your neck and armpits
  • Rash
  • Swollen liver, spleen, or both (these are less common symptoms)

Most people get better in two to four weeks. However, some people may feel fatigued for several more weeks. Occasionally, the symptoms can last for six months or longer.

How is infectious mononucleosis (mono) diagnosed?

Your healthcare provider may diagnose mono based on your symptoms and a physical exam. The exam will include checking to see if your lymph nodes, tonsils, liver, or spleen are swollen. In some cases, your provider might also order a mono test to confirm the diagnosis.

What are the treatments for infectious mononucleosis (mono)?

  • Drinking plenty of fluids to avoid dehydration.
  • Getting lots of rest.
  • Taking over-the-counter medications for pain and fever. But don't give aspirin to children or teens because it may cause Reye syndrome. This syndrome is a rare, serious illness that can affect the brain and liver.

If you have severe symptoms, your provider may suggest additional treatment based on which organs in your body are affected by the mono.

Antibiotics don't treat viral infections, so they do not help with mono. Some people do get bacterial infections such as strep throat along with mono. In that case, you probably need antibiotics to treat the bacterial infection. But you should not take penicillin antibiotics like ampicillin or amoxicillin. Those antibiotics can cause a rash in people who have mono.

Mono can cause an enlarged spleen, which could rupture and cause a medical emergency. To try to protect the spleen, providers recommend avoiding intense exercise and contact sports until you fully recover (about a month).

Can infectious mononucleosis (mono) be prevented?

There is no vaccine to protect against mono. To lower your chance of getting or spreading mono:

  • Don't share food, drinks, forks, spoons, or lip balm with anyone, especially if you or the other person has mono.
  • Don't kiss someone if you or the other person has mono.
  • Wash your hands often with soap and water.

Centers for Disease Control and Prevention


[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.