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ICD10BillableValid for clinical use

ICD-10 Code B59: Pneumocystosis

B59 is a billable ICD-10 diagnosis code used to classify Pneumocystosis in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Certain infectious and parasitic diseases (A00-B99).

When is it used?

  • May be used when a clinician documents pneumocystosis in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
1Certain infectious and parasitic diseases (A00-B99)
block
B50-B64Protozoal diseases
currentB50-B64

Official coding notes

Inclusion terms
  • Pneumonia due to Pneumocystis carinii
  • Pneumonia due to Pneumocystis jirovecii

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

Infectious Disease SpecialistGeneral Physician

Coverage-related procedures and services

CPT 87801high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA), MULTIPLE ORGANISMS; AMPLIFIED PROBE(S) TECHNIQUE
Source: CMS coverage guidance
CPT 87631high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); RESPIRATORY VIRUS (EG, ADENOVIRUS, INFLUENZA VIRUS, CORONAVIRUS, METAPNEUMOVIRUS, PARAINFLUENZA VIRUS, RESPIRATORY SYNCYTIAL VIRUS, RHINOVIRUS), INCLUDES MULTIPLEX REVERSE TRANSCRIPTION, WHEN PERFORMED, AND MULTIPLEX AMPLIFIED PROBE TECHNIQUE, MULTIPLE TYPES OR SUBTYPES, 3-5 TARGETS
Source: CMS coverage guidance
CPT 87636high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); SEVERE ACUTE RESPIRATORY SYNDROME CORONAVIRUS 2 (SARS-COV-2) (CORONAVIRUS DISEASE [COVID-19]) AND INFLUENZA VIRUS TYPES A AND B, MULTIPLEX AMPLIFIED PROBE TECHNIQUE
Source: CMS coverage guidance
CPT 87637high
INFECTIOUS AGENT DETECTION BY NUCLEIC ACID (DNA OR RNA); SEVERE ACUTE RESPIRATORY SYNDROME CORONAVIRUS 2 (SARS-COV-2) (CORONAVIRUS DISEASE [COVID-19]), INFLUENZA VIRUS TYPES A AND B, AND RESPIRATORY SYNCYTIAL VIRUS, MULTIPLEX AMPLIFIED PROBE TECHNIQUE
Source: CMS coverage guidance
CPT 81479high
UNLISTED MOLECULAR PATHOLOGY PROCEDURE
Source: CMS coverage guidance
CPT 94642high
AEROSOL INHALATION OF PENTAMIDINE FOR PNEUMOCYSTIS CARINII PNEUMONIA TREATMENT OR PROPHYLAXIS
Source: CMS coverage guidance

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
B59

Common synonyms

Pneumocystosis

Frequently asked questions

Code details

CodeB59
SystemICD10
Display namePneumocystosis
ChapterCertain infectious and parasitic diseases (A00-B99)
BlockProtozoal diseases

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Disease, diseasedInfection, infected, infective(opportunistic)Infection, infected, infective(opportunistic)Pneumocystis carinii pneumoniaPneumocystis jirovecii(pneumonia)Pneumocystosis(with pneumonia)Pneumonia(acute) (double) (migratory) (purulent) (septic) (unresolved)Pneumonia(acute) (double) (migratory) (purulent) (septic) (unresolved)Pneumonia(acute) (double) (migratory) (purulent) (septic) (unresolved)Pneumonia(acute) (double) (migratory) (purulent) (septic) (unresolved)

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code B59 for Pneumocystosis | HealthAssure