2027 ICD-10-CM Diagnosis Code A33Tetanus neonatorum
ICD-10-CM Codes›A00–B99›A30-A49›A33
- Billable — Valid for Submission
- MCC — Major Complication or Comorbidity
- Not Chronic
A33 is a billable ICD-10-CM diagnosis code for tetanus neonatorum. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 794. 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 18 closely related codes. The code is restricted by the Medicare Code Editor to newborn patients (age 0). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Perinatal infections.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for A33.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Autonomic disorder due to tetanus
- Disorder of autonomic nervous system due to infectious disease
- Hypertonia of muscle of limb
- Hypertonia of muscle of lower limb
- Hypertonia of muscle of neck
- Hypertonia of muscle of trunk
- Localized tetanus
- Muscular hypertonicity
- Omphalitis
- Tetanic opisthotonus
- Tetanus neonatorum
- Tetanus omphalitis
- Tetanus with trismus
- Trismus
- Trismus present
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to A33: its own notes plus those printed at Chapter 1. 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.
- diseases generally recognized as communicable or transmissible
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.
- 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)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name A33, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming A33: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 3
These codes carry an Excludes2 note naming A33: its condition is not part of those codes, and both may be reported when the patient has both.
- Chapter 16 (P00-P96) Certain conditions originating in the perinatal periodtetanus neonatorum (A33)
- Block P35-P39 Infections specific to the perinatal periodtetanus neonatorum (A33)
- P37 Other congenital infectious and parasitic diseasestetanus neonatorum (A33)
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
neonatorum A33
newborn A33
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Tetanus Neonatorum
a syndrome of generalized rigidity with muscle spasms and seizures in the neonatal period resulting from clostridium tetani toxin production.
Patient EducationClinical
Tetanus
Tetanus is a serious illness caused by Clostridium bacteria. The bacteria live in soil, saliva, dust, and manure. The bacteria can enter the body through a deep cut, like those you might get from stepping on a nail, or through a burn.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert A33 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About A33Overview
What is the ICD-10 code for tetanus neonatorum?
The ICD-10-CM code for tetanus neonatorum is A33. It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is A33 (Tetanus neonatorum) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report tetanus neonatorum on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does A33 group to?
When tetanus neonatorum is the principal diagnosis on an inpatient stay, it groups to MS-DRG 794 (neonate with Other Significant Problems), which carries a relative weight of 1.4934. Higher weights mean higher Medicare reimbursement.
Is A33 a CC or MCC?
CMS lists A33 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 18 closely related codes in its exclusion list.
Who can A33 be reported for?
The Medicare Code Editor checks tetanus neonatorum against patient demographics: this code is intended for newborn patients (age 0). Claims outside these limits are flagged as inconsistent.
