2026 ICD-10-CM Diagnosis Code P37.1Congenital toxoplasmosis

ICD-10-CM Codes›P00–P96›P35-P39›P37

ICD-10-CM P37.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

P37.1 is a billable ICD-10-CM diagnosis code for congenital toxoplasmosis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 791, 793. As a secondary diagnosis, it counts as a major complication or comorbidity (MCC) and places an inpatient stay in the highest severity level of its MS-DRG family. It does not count, however, when the principal diagnosis is one of 188 closely related codes. Coders also document this condition as congenital disseminated toxoplasmosis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections; and Perinatal infections.

Code Identity

ICD-10-CM Code
P37.1
Billable Status
Yes — Valid for Submission
Code Describes
Congenital toxoplasmosis
Short Description
Congenital toxoplasmosis
Same as the full description in the CMS dataset.
Parent Code
P37
Other congenital infectious and parasitic diseases

Code Classification

ChapterP00–P96Certain conditions originating in the perinatal period
SectionP35-P39Infections specific to the perinatal period
CategoryP37Other congenital infectious and parasitic diseases
This CodeP37.1Congenital toxoplasmosis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Congenital disseminated toxoplasmosis
  • Congenital hydrocephalus caused by toxoplasmosis
  • Congenital toxoplasmosis
  • Lymphadenopathy due to congenital toxoplasmosis
  • Multisystemic disseminated toxoplasmosis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Hydrocephalus due to congenital toxoplasmosis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient No · outpatient No
CCSR PNL009
Perinatal infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Congenital Toxoplasmosis

    toxoplasma infection that is present from birth.

Patient EducationClinical

Uncommon Infant and Newborn Problems

It can be scary when your baby is sick, especially when it is not an everyday problem like a cold or a fever. You may not know whether the problem is serious or how to treat it. If you have concerns about your baby's health, call your health care provider right away.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert P37.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
771.2 Congenital infec NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About P37.1Overview

What is the ICD-10 code for congenital toxoplasmosis?

The ICD-10-CM code for congenital toxoplasmosis is P37.1 (sometimes written as P371). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is P37.1 (Other congenital infectious and parasitic diseases) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital toxoplasmosis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does P37.1 group to?

When congenital toxoplasmosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 791, 793, with relative weights from 4.0590 to 4.1696 depending on complications. Higher weights mean higher Medicare reimbursement.

Is P37.1 a CC or MCC?

CMS lists P37.1 as an MCC (major complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it places the inpatient stay in the highest-weighted DRG of its severity family. It does not count when the principal diagnosis is one of the 188 closely related codes in its exclusion list.

What is the ICD-9 equivalent of P37.1?

Under the General Equivalence Mappings, congenital toxoplasmosis converts to ICD-9-CM 771.2 (congenital infec NEC). The mapping is approximate, so confirm the match fits the documentation.