Is ICD-10-CM code A77 billable?

No, A77 (Spotted fever [tick-borne rickettsioses]) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code A77 belong to?

A77 belongs to Chapter 1 of the ICD-10-CM tabular list: A00–B99 (Certain Infectious and Parasitic Diseases).

A77Not billable, use a more specific code below

Spotted fever [tick-borne rickettsioses]

In Rickettsioses (A75-A79), chapter 1: Certain Infectious and Parasitic Diseases

9 billable codes under A77: all are a CC; none map to an HCC.A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment.

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)

Read Section I.C.1 (page 19)

All codes under A77

A77 can't be used on a claim. Pick a billable code below; grey headings group them.

A77 MS-DRGs

As the principal diagnosis, all 9 billable codes under A77 group 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.

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Bacterial Infections

Bacteria are tiny organisms (living things) that have only one cell. Under a microscope, they look like balls, rods, or spirals. They can be found almost everywhere on Earth. There are lots of bacteria in and on your body. In fact, your body has about 10 times more bacteria cells than human cells.

Tick Bites

Ticks are small parasites. They may look like insects, but they have eight legs and are related to spiders. Ticks feed on the blood of people and warm-blooded animals. There are many types of ticks in the United States, and they live in different parts of the country.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.