Unspecified protozoal disease
In Protozoal diseases (B50-B64), chapter 1: Certain Infectious and Parasitic Diseases
- B64 is an unspecified code: use it only when the record doesn't document anything more specific. If the record has more detail, check the other codes under B50-B64 below.
- As a secondary diagnosis it is not a CC or MCC, so it doesn't raise the MS-DRG payment.
- Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
- AHRQ's Chronic Condition Indicator classes it as not chronic (an acute or short-term condition).
Also indexed as: Disease, protozoal; Infection, protozoal NEC; Infestation, protozoal NEC; Protozoal, disease
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Instructional notes
Official coding guidelines
From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.
Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.
- Human Immunodeficiency Virus (HIV) Infections (page 19)
- Infectious agents as the cause of diseases classified to other chapters (page 22)
- Infections resistant to antibiotics (page 22)
- Sepsis, Severe Sepsis, and Septic Shock (page 23)
- Methicillin Resistant Staphylococcus aureus (MRSA) Conditions (page 27)
- Zika virus infections (page 28)
- Coronavirus infections (page 28)
Other codes under B50-B64
Protozoal diseases (B50-B64)
- B50Plasmodium falciparum malaria
- B51Plasmodium vivax malaria
- B52Plasmodium malariae malaria
- B53Other specified malaria
- B54Unspecified malaria
- B55Leishmaniasis
- B56African trypanosomiasis
- B57Chagas' disease
- B58Toxoplasmosis
- B59Pneumocystosis
- B60Other protozoal diseases, not elsewhere classified
- B64Unspecified protozoal disease(this code)
B64 MS-DRGs
As the principal diagnosis, B64 groups to MS-DRG 867, 868, or 869 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.
Related conditions
Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.
B64 is in Parasitic, other specified and unspecified infections (INF009, its default category), with 254 codes. Others in it:
Other codes that refer to B64
Notes on these codes point to B64.
- O98.6 Includes: Conditions in B50-B64
About the condition
Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.
Parasitic Diseases
Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.
Read more about parasitic diseases on MedlinePlusCode history
Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.
ICD-9-CM equivalent
Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).
- 088.9 Arthropod-borne disease, unspecified (approximate)
- 136.9 Unspecified infectious and parasitic diseases (approximate)