ICD-10-CM 2027 diagnosis code

A37.9Whooping cough, unspecified species

Not billable — use a more specific code

A37.9 is a header code, so it can't be reported by itself. Choose one of the 2 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About A37.9

A37.9 is the ICD-10-CM diagnosis code for whooping cough, unspecified species. It belongs to category A37 (whooping cough), block A30-A49 (other bacterial diseases) and chapter 1 (certain infectious and parasitic diseases). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within A37, choose A37.9 (unspecified species) only when documentation doesn't support a more specific option: due to Bordetella pertussis (A37.0), due to Bordetella parapertussis (A37.1) and due to other Bordetella species (A37.8).

To report this condition, pick the subcode that matches the documentation: A37.90 (without pneumonia) and A37.91 (with pneumonia).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under A37.9

Notes that apply from higher levels

Instructions written at a parent level also apply to A37.9.

Broader instructions also apply from Chapter 1: Certain infectious and parasitic diseases.

Code history

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2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about A37.9

Is A37.9 billable?: No. A37.9 is a header code. Report one of its more specific subcodes instead.