A52.12

Other cerebrospinal syphilis

FY2027Chapter 1: Certain infectious and parasitic diseases/A50–A64 Infections with a predominantly sexual mode of transmission

BillableComplete code, valid to report

A52.12 (also written A5212) is a billable ICD-10-CM diagnosis code for other cerebrospinal syphilis. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 30 codes in category A52 (Late syphilis). The Alphabetic Index lists it under 6 entries. Its coding notes include a Use additional code instruction, 2 Excludes1 entries and 6 Excludes2 entries.

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (1 note)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • code to identify resistance to antimicrobial drugs (Z16.-)

Excludes1

Not coded here. The listed conditions generally should not be reported together.

Also from chapter/block level (2 notes)
Inherited from A50–A64 Infections with a predominantly sexual mode of transmission
  • nonspecific and nongonococcal urethritis (N34.1)
  • Reiter's disease (M02.3-)

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Also from chapter/block level (6 notes)
Inherited from A50–A64 Infections with a predominantly sexual mode of transmission
  • human immunodeficiency virus [HIV] disease (B20)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • carrier or suspected carrier of infectious disease (Z22.-)
  • certain localized infections - see body system-related chapters
  • infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
  • infectious and parasitic diseases specific to the perinatal period (P35-P39)
  • influenza and other acute respiratory infections (J00-J22)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Home Health Primary

Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Neuro Rehabilitation clinical group.

Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 96 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

IPF Primary

IPF MS-DRG adjustment. A principal diagnosis of this code groups to one of these MS-DRGs. Which one depends on other facts of the stay, so the factor is a range:

MS-DRGDescriptionFactor
056Degenerative nervous system disorders w MCC1.12
057Degenerative nervous system disorders w/o MCC1.11
A principal diagnosis that groups to none of the 19 designated MS-DRGs gets no MS-DRG adjustment. Otherwise the claim still receives the federal per diem base rate and the other adjustments.

Source: CMS IPF PPS FY 2027 final rule (CMS-1847-F), Addendum A; code lists from the CMS MS-DRG Definitions Manual v44; effective for discharges on or after October 1, 2026

Includes

Further defines or gives examples of the content of the category.

Also from chapter/block level (1 note)
Inherited from Chapter 1 Certain infectious and parasitic diseases
  • diseases generally recognized as communicable or transmissible

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 6 entries