Is ICD-10-CM code A50 billable?

No, A50 (Congenital syphilis) 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 A50 belong to?

A50 belongs to Chapter 1 of the ICD-10-CM tabular list: A00–B99 (Certain Infectious and Parasitic Diseases).

A50Not billable, use a more specific code below

Congenital syphilis

In Infections with a predominantly sexual mode of transmission (A50-A64), chapter 1: Certain Infectious and Parasitic Diseases

33 billable codes under A50: 2 are an MCC, 27 are a CC; 1 map to HCC 92 (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Also applies, from Infections with a predominantly sexual mode of transmission (A50-A64)

These notes sit on A50-A64 and apply to every code under it, including A50.

Excludes1: not coded here, use a different code

nonspecific and nongonococcal urethritis (N34.1)
Reiter's disease (M02.3-)

Excludes2: not included here, code separately if applicable

human immunodeficiency virus [HIV] disease (B20)

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 A50

A50 can't be used on a claim. Pick a billable code below; grey headings group them.

A50 MS-DRGs

As the principal diagnosis, the billable codes under A50 group to these 8 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 867 Other Infectious and Parasitic Diseases Diagnoses with MCC (26 of 33 codes)
DRG 868 Other Infectious and Parasitic Diseases Diagnoses with CC (26 of 33 codes)
DRG 869 Other Infectious and Parasitic Diseases Diagnoses without CC/MCC (26 of 33 codes)
DRG 097 Non-Bacterial Infection of Nervous System Except Viral Meningitis with MCC (6 of 33 codes)
DRG 098 Non-Bacterial Infection of Nervous System Except Viral Meningitis with CC (6 of 33 codes)
DRG 099 Non-Bacterial Infection of Nervous System Except Viral Meningitis without CC/MCC (6 of 33 codes)
DRG 124 Other Disorders of the Eye with MCC or Thrombolytic Agent (1 of 33 codes)
DRG 125 Other Disorders of the Eye without MCC (1 of 33 codes)

Other codes that refer to A50

Notes on these codes point to A50.

A65-A69 Excludes2: syphilis (A50-A53)
J99 Code First: congenital syphilis (A50.-)
N34 Excludes2: urethritis in diseases with a predominantly sexual mode of transmission (A50-A64)
O98.1 Includes: Conditions in A50-A53
P35-P39 Excludes2: congenital syphilis (A50.-)
P37 Excludes2: congenital syphilis (A50.-)

About the condition

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

Syphilis

Syphilis is a sexually transmitted infection (STI) caused by bacteria. It infects the genital area, lips, mouth, or anus of both men and women. You usually get syphilis from sexual contact with someone who has it. It can also pass from mother to baby during pregnancy.

Code history

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