2027 ICD-10-CM Diagnosis Code G37.3Acute transverse myelitis in demyelinating disease of central nervous system
ICD-10-CM Codes›G00–G99›G35-G37›G37
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 182
- Chronic Condition
G37.3 is a billable ICD-10-CM diagnosis code for acute transverse myelitis in demyelinating disease of central nervous system. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 23 through 24, 97 through 99. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 220 closely related codes. Coders also document this condition as acute non-infective transverse myelitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).
For Medicare Advantage risk adjustment, G37.3 maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries) under the V28 model, adding a risk factor of about 0.478 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
G37.3 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acute non-infective transverse myelitis
- Acute transverse myelitis
- Acute viral transverse myelitis
- Complete transverse myelitis
- Idiopathic transverse myelitis
- Transverse myelopathy syndrome
- Varicella transverse myelitis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to G37.3: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.
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.
- Acute transverse myelitis NOS
- Acute transverse myelopathy
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
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.
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
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.
Patient EducationClinical
Degenerative Nerve Diseases
Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert G37.3 to ICD-9-CMHistory
Code HistoryHistory
Questions About G37.3Overview
Is G37.3 (Other demyelinating diseases of central nervous system) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report acute transverse myelitis in demyelinating disease of central nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does G37.3 group to?
When acute transverse myelitis in demyelinating disease of central nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 24, 98, 99, 23, 97, with relative weights from 1.5249 to 5.7422 depending on complications. Higher weights mean higher Medicare reimbursement.
Is G37.3 a CC or MCC?
CMS lists G37.3 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 220 closely related codes in its exclusion list.
Can G37.3 be reported with G04.82?
Not as a rule. The Excludes1 note on G37.3 lists "acute flaccid myelitis (G04.82)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of G37.3?
Under the General Equivalence Mappings, acute transverse myelitis in demyelinating disease of central nervous system converts to ICD-9-CM 341.20 (acute myelitis NOS) and 341.21 (acute myelitis oth cond). The mapping is approximate, so confirm the match fits the documentation.
What HCC is G37.3?
G37.3 (acute transverse myelitis in demyelinating disease of central nervous system) maps to CMS-HCC Category 182 (Spinal Cord Disorders/Injuries), commonly written as HCC 182, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 72 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 155.
Does G37.3 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, G37.3 adds a risk adjustment factor of about 0.478 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.270 to 0.478 depending on the payment segment). A more severe related category (HCC 180, HCC 181, HCC 191, and HCC 192) supersedes it when both are reported. See the full factor table on the HCC 182 category page.
