2027 ICD-10-CM Diagnosis Code P37.1Congenital toxoplasmosis
ICD-10-CM Codes›P00–P96›P35-P39›P37
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Not Chronic
P37.1 is a billable ICD-10-CM diagnosis code for congenital toxoplasmosis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) 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
Code Classification
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
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to P37.1: its own notes plus those printed at P37, block P35-P39, and Chapter 16. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- conditions that have their origin in the fetal or perinatal period (before birth through the first 28 days after birth) even if morbidity occurs later
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Hydrocephalus due to congenital toxoplasmosis
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
- asymptomatic human immunodeficiency virus [HIV] infection status (Z21)
- congenital gonococcal infection (A54.-)
- congenital pneumonia (P23.-)
- congenital syphilis (A50.-)
- human immunodeficiency virus [HIV] disease (B20)
- infant botulism (A48.51)
- infectious diseases not specific to the perinatal period (A00-B99, J09, J10.-)
- intestinal infectious disease (A00-A09)
- laboratory evidence of human immunodeficiency virus [HIV] (R75)
- tetanus neonatorum (A33)
Notes
General instructions on how these codes are used.
- Codes from this chapter are for use on newborn records only, never on maternal records
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name P37.1, its category, or a range that includes it.
Excludes1 3
These codes carry an Excludes1 note naming P37.1: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 2
These codes carry an Excludes2 note naming P37.1: its condition is not part of those codes, and both may be reported when the patient has both.
- Chapter 1 (A00-B99) Certain infectious and parasitic diseases
- P00.2 Newborn affected by maternal infectious and parasitic diseases
Code First 3
These codes say to code first a condition named in the note, and P37.1 is one of the conditions named.
- G05 Encephalitis, myelitis and encephalomyelitis in diseases classified elsewherecongenital toxoplasmosis encephalitis, myelitis and encephalomyelitis (P37.1)
- H32 Chorioretinal disorders in diseases classified elsewherecongenital toxoplasmosis (P37.1)
- K77 Liver disorders in diseases classified elsewherecongenital toxoplasmosis (P37.1)
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Chorioretinitis See Also: Inflammation, chorioretinal;
Meningoencephalitis See Also: Encephalitis; G04.90
Meningoencephalomyelitis See Also: Meningoencephalitis;
Pneumonitis (acute) (primary) See Also: Pneumonia; J98.4
Uveitis (anterior) See Also: Iridocyclitis;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Toxoplasmosis, Congenital
prenatal protozoal infection with toxoplasma gondii which is associated with injury to the developing fetal nervous system. the severity of this condition is related to the stage of pregnancy during which the infection occurs; first trimester infections are associated with a greater degree of neurologic dysfunction. clinical features include hydrocephalus; microcephaly; deafness; cerebral calcifications; seizures; and psychomotor retardation. signs of a systemic infection may also be present at birth, including fever, rash, and hepatosplenomegaly. (from adams et al., principles of neurology, 6th ed, p735)
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.
Code HistoryHistory
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, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
What MS-DRG does P37.1 group to?
When congenital toxoplasmosis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, with relative weights from 4.1073 to 4.2192 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 2027. 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.
