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B59

B59Pneumocystosis

Billable / specific codeICD-10-CM

B59 is a billable, specific ICD-10-CM code for pneumocystosis. It is valid for submission on a claim.

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Pneumonia due to Pneumocystis carinii
  • Pneumonia due to Pneumocystis jirovecii

Other codes that can never be billed with B59

These codes carry an Excludes1 note pointing at B59. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading B59 alone.

  • J16Pneumonia due to other infectious organisms, not elsewhere classified
  • J17Pneumonia in diseases classified elsewhere
  • J84.11Idiopathic interstitial pneumonia
  • J84.114Acute interstitial pneumonitis

Risk adjustment

B59 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

  • HCC 6 Opportunistic Infections0.381 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

B59 is named in 18 Medicare coverage policies 18 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A52466Nebulizers - Policy Article
  • A52466Nebulizers - Policy Article
  • A52466Nebulizers - Policy Article
  • A52466Nebulizers - Policy Article

How B59 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to B59.

  • Pneumocystis carinii pneumonia
  • Pneumocystis jirovecii(pneumonia)
  • Pneumocystosis(with pneumonia)
  • Infection, infected, infectivePneumocystis carinii(pneumonia)
  • Infection, infected, infectivePneumocystis jirovecii(pneumonia)
  • Pneumoniaplasma cell(of infants)
  • PneumoniaPneumocystis(carinii) (jirovecii)
  • Disease, diseasedprotozoalpneumocystosis
  • Pneumoniainpneumocystosis(Pneumocystis carinii) (Pneumocystis jirovecii)
  • Pneumoniainterstitialplasma cell

Questions about B59

Is B59 a billable ICD-10-CM code?
Yes. B59 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does B59 sit in the tabular list?
Certain infectious and parasitic diseases (A00-B99), in the block Protozoal diseases (B50-B64).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.