ICD-10 G93.40
Billable / Specific CCEncephalopathy, unspecified
About ICD-10-CM G93.40
ICD-10-CM code G93.40 represents Encephalopathy, unspecified. This is a billable/specific code in the Nervous System chapter (block G93). The 2026 edition of ICD-10-CM G93.40 became effective on October 1, 2025.
Coding Tips for G93.40
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
G93.40 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inpatient DRG Impact, CC
codes Encephalopathy, unspecified. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for G93.40
Local Coverage Determinations (LCDs) from CMS MACs that list G93.40 as a covered diagnosis.
Showing top 10 of 56 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G93.40.
1 Cigna
5 Medicare
2 Aetna
CPT Codes Commonly Billed with G93.40
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 99205 New patient office visit — complex/high-risk: uncontrolled diabetes, heart failure, COPD exacerbation, cancer, MS, RA, CKD, CAD, recurrent depression, epilepsy, lupus, syncope, cognitive decline Primary Care
- 99215 Established patient — high complexity: HF exacerbation, COPD exacerbation, cancer management, MS, advanced CKD, uncontrolled diabetes, recurrent syncope, respiratory failure, liver cirrhosis Primary Care
- 70553 MRI brain with and without contrast — migraine, headache, encephalopathy, brain cancer, epilepsy, brain neoplasm, cognitive decline, MS, hydrocephalus, aphasia, numbness Radiology
- 70551 MRI brain without contrast — migraine, headache, encephalopathy, cognitive decline, MS, epilepsy, syncope, dizziness Radiology
- 99285 ED visit level 5 — STEMI, massive PE, respiratory failure, cardiogenic shock, cardiac arrest, ICH, encephalopathy, coma, anaphylaxis, SAH, ARDS, compartment syndrome Emergency Medicine
- 95819 EEG awake and asleep — epilepsy, generalized seizures, absence seizures, focal seizures, seizure NOS, fasciculations, syncope, encephalopathy, cognitive decline, aphasia, migraine, headache, insomnia Neurology
- 95816 EEG awake only — epilepsy, seizures, encephalopathy, cognitive decline, syncope Neurology
Convert G93.40 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| G93.40 | 34830 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To G93.40
Other codes in section G89-G99 (Other disorders of the nervous system).
ICD-10 G93.40, Billing FAQ
Is ICD-10 code G93.40 billable? +
Yes, G93.40 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Is G93.40 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with G93.40? +
Procedures frequently paired with G93.40 include: 99205, 99215, 70553, 70551, 99285.
What ICD-9 codes does G93.40 map to? +
Per CMS GEMs, G93.40 maps to ICD-9 codes: 34830. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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