ICD-10-CM
ICD-10 code for Exposure (to) cyanobacteria bloom: Z77.121
The ICD-10-CM index points "Exposure (to) cyanobacteria bloom" to Z77.121, Contact with and (suspected) exposure to harmful algae and algae toxins. Z77.121 is a billable code.
Source: CDC ICD-10-CM FY2027 Alphabetic Index file dated June 16, 2026. Publisher page
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More specific codes in Z77
A header groups codes and is not billed. A billable code is one you can report.
- Z77Other contact with and (suspected) exposures hazardous to healthHeader
- Z77.0Contact with and (suspected) exposure to hazardous, chiefly nonmedicinal, chemicalsHeader
- Z77.01Contact with and (suspected) exposure to hazardous metalsHeader
- Z77.010Contact with and (suspected) exposure to arsenicBillable
- Z77.011Contact with and (suspected) exposure to leadBillable
- Z77.012Contact with and (suspected) exposure to uraniumBillable
- Z77.013Contact with and (suspected) exposure to gadoliniumBillable
- Z77.018Contact with and (suspected) exposure to other hazardous metalsBillable
- Z77.02Contact with and (suspected) exposure to hazardous aromatic compoundsHeader
- Z77.020Contact with and (suspected) exposure to aromatic aminesBillable
- Z77.021Contact with and (suspected) exposure to benzeneBillable
- Z77.028Contact with and (suspected) exposure to other hazardous aromatic compoundsBillable
- Z77.09Contact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicalsHeader
- Z77.090Contact with and (suspected) exposure to asbestosBillable
- Z77.098Contact with and (suspected) exposure to other hazardous, chiefly nonmedicinal, chemicalsBillable
- Z77.1Contact with and (suspected) exposure to environmental pollution and hazards in the physical environmentHeader
- Z77.11Contact with and (suspected) exposure to environmental pollutionHeader
- Z77.110Contact with and (suspected) exposure to air pollutionBillable
- Z77.111Contact with and (suspected) exposure to water pollutionBillable
- Z77.112Contact with and (suspected) exposure to soil pollutionBillable
- Z77.118Contact with and (suspected) exposure to other environmental pollutionBillable
- Z77.12Contact with and (suspected) exposure to hazards in the physical environmentHeader
- Z77.120Contact with and (suspected) exposure to mold (toxic)Billable
- Z77.121Contact with and (suspected) exposure to harmful algae and algae toxinsBillable
- Z77.122Contact with and (suspected) exposure to noiseBillable
- Z77.123Contact with and (suspected) exposure to radon and other naturally occurring radiationBillable
- Z77.128Contact with and (suspected) exposure to other hazards in the physical environmentBillable
- Z77.2Contact with and (suspected) exposure to other hazardous substancesHeader
- Z77.21Contact with and (suspected) exposure to potentially hazardous body fluidsBillable
- Z77.22Contact with and (suspected) exposure to environmental tobacco smoke (acute) (chronic)Billable
- Z77.29Contact with and (suspected) exposure to other hazardous substancesBillable
- Z77.3Contact with and (suspected) exposure to war theaterHeader
- Z77.31Contact with and (suspected) exposure to Gulf War theaterBillable
- Z77.32Contact with and (suspected) exposure to burn pits in war theaterBillable
- Z77.33Contact with and (suspected) exposure to Agent OrangeBillable
- Z77.39Contact with and (suspected) exposure to other war theaterBillable
- Z77.4Contact with and (suspected) exposure to blast overpressureHeader
- Z77.40Contact with and (suspected) exposure to unspecified blast overpressureBillable
- Z77.41Contact with and (suspected) exposure to low-level blast overpressureBillable
- Z77.42Contact with and (suspected) exposure to high-level blast overpressureBillable
- Z77.49Contact with and (suspected) exposure to other blast overpressureBillable
- Z77.9Other contact with and (suspected) exposures hazardous to healthBillable
Excludes2
Excludes2 means the other condition can be reported with this one when both are documented.
From Z77. A note on a category applies to every code under it.
- Z20.-Contact with and (suspected) exposure to communicable diseases
- P96.81Exposure to (parental) (environmental) tobacco smoke in the perinatal period
- P04.-Newborn affected by noxious substances transmitted via placenta or breast milk
- Z57.-Occupational exposure to risk factors
- Z18.-Retained foreign body
- Z87.821Retained foreign body fully removed
- T51-T65Toxic effects of substances chiefly nonmedicinal as to source
Related conditions
Related pages
- Z77.121 code detailsNotes, nearby codes, CMS-HCC group
- Category Z77Every code under it
- Chapter 21Factors influencing health status
- ICD-10 codes by conditionA to Z
- Check a list of ICD-10 codes
- Denial code CO-11Diagnosis does not support the procedure
- Denial code CO-146Diagnosis invalid for the date of service
- HCPCS Level II code lookup
Questions
What is the ICD-10 code for Exposure (to) cyanobacteria bloom?
The ICD-10-CM index points "Exposure (to) cyanobacteria bloom" to Z77.121, Contact with and (suspected) exposure to harmful algae and algae toxins. Z77.121 is a billable code.
Is Z77.121 billable?
Yes. Z77.121 is a billable code in the FY2027 ICD-10-CM file. Use a more specific code when the record documents one.
What documentation notes apply to Z77.121?
The CDC tabular list gives 7 Excludes2 notes (may be coded together when both are documented) for Z77.121 and the categories above it. They are listed on this page.
What chapter is Z77.121 in?
Chapter 21. Factors influencing health status.
When do ICD-10-CM codes change?
Every October 1, with the new fiscal year file. Some years add April 1 updates. This page uses the FY2027 file, effective October 1, 2026.