2022 ICD-10-CM Code D81.5

Purine nucleoside phosphorylase [PNP] deficiency

Version 2021

Valid for Submission

ICD-10:D81.5
Short Description:Purine nucleoside phosphorylase [PNP] deficiency
Long Description:Purine nucleoside phosphorylase [PNP] deficiency

Code Classification

  • Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50–D89)
    • Certain disorders involving the immune mechanism (D80-D89)
      • Combined immunodeficiencies (D81)

D81.5 is a billable diagnosis code used to specify a medical diagnosis of purine nucleoside phosphorylase [pnp] deficiency. The code D81.5 is valid during the fiscal year 2022 from October 01, 2021 through September 30, 2022 for the submission of HIPAA-covered transactions.

The ICD-10-CM code D81.5 might also be used to specify conditions or terms like purine-nucleoside phosphorylase deficiency.

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 D81.5 are found in the index:

Approximate Synonyms

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

Convert D81.5 to ICD-9 Code

The General Equivalency Mapping (GEM) crosswalk indicates an approximate mapping between the ICD-10 code D81.5 its ICD-9 equivalent. The approximate mapping means there is not an exact match between the ICD-10 code and the ICD-9 code and the mapped code is not a precise representation of the original code.

Information for Patients


Immune System and Disorders

What is the immune system?

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

When germs such as bacteria or viruses invade your body, they attack and multiply. This is called an infection. The infection causes the disease that makes you sick. Your immune system protects you from the disease by fighting off the germs.

What are the parts of the immune system?

The immune system has many different parts, including

How does the immune system work?

Your immune system defends your body against substances it sees as harmful or foreign. These substances are called antigens. They may be germs such as bacteria and viruses. They might be chemicals or toxins. They could also be cells that are damaged from things like cancer or sunburn.

When your immune system recognizes an antigen, it attacks it. This is called an immune response. Part of this response is to make antibodies. Antibodies are proteins that work to attack, weaken, and destroy antigens. Your body also makes other cells to fight the antigen.

Afterwards, your immune system remembers the antigen. If it sees the antigen again, it can recognize it. It will quickly send out the right antibodies, so in most cases, you don't get sick. This protection against a certain disease is called immunity.

What are the types of immunity?

There are three different types of immunity:

What can go wrong with the immune system?

Sometimes a person may have an immune response even though there is no real threat. This can lead to problems such as allergies, asthma, and autoimmune diseases. If you have an autoimmune disease, your immune system attacks healthy cells in your body by mistake.

Other immune system problems happen when your immune system does not work correctly. These problems include immunodeficiency diseases. If you have an immunodeficiency disease, you get sick more often. Your infections may last longer and can be more serious and harder to treat. They are often genetic disorders.

There are other diseases that can affect your immune system. For example, HIV is a virus that harms your immune system by destroying your white blood cells. If HIV is not treated, it can lead to AIDS (acquired immunodeficiency syndrome). People with AIDS have badly damaged immune systems. They get an increasing number of severe illnesses.


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Purine nucleoside phosphorylase deficiency

Purine nucleoside phosphorylase deficiency is a disorder of the immune system called an immunodeficiency. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria and viruses.

People with purine nucleoside phosphorylase deficiency have low numbers of immune system cells called T cells, which normally recognize and attack foreign invaders to prevent infection. Some affected individuals also have low numbers of other immune system cells called B cells, which normally help fight infections by producing immune proteins called antibodies (or immunoglobulins). These proteins target foreign invaders and mark them for destruction. The most severely affected individuals, who lack T cells and B cells, have a serious condition called severe combined immunodeficiency (SCID).

The shortage of immune system cells in people with purine nucleoside phosphorylase deficiency results in repeated and persistent infections typically beginning in infancy or early childhood. Infections most commonly affect the sinuses and lungs. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. The infections can be very serious or life-threatening, and without successful treatment to restore immune function, children with purine nucleoside phosphorylase deficiency usually do not survive past childhood.

Infants with purine nucleoside phosphorylase deficiency typically grow more slowly than healthy babies. About two-thirds of individuals with this condition also have neurological problems, which may include developmental delay, intellectual disability, difficulty with balance and coordination (ataxia), and muscle stiffness (spasticity). People with purine nucleoside phosphorylase deficiency are also at increased risk of developing autoimmune disorders, which occur when the immune system malfunctions and attacks the body's tissues and organs.


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Code History

  • 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 (First year ICD-10-CM implemented into the HIPAA code set)