ICD-10 T40.416
Non-Billable HeaderUnderdosing of fentanyl or fentanyl analogs
About ICD-10-CM T40.416
ICD-10-CM code T40.416 represents Underdosing of fentanyl or fentanyl analogs. This is a non-billable header code in the Injury, Poisoning, and External Causes chapter (block T40). The 2026 edition of ICD-10-CM T40.416 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Coding Tips for T40.416
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
Injury codes require a 7th character: A (initial encounter, active treatment), D (subsequent, healing/recovery), S (sequela, late effect of original injury). Codes with fewer than 6 characters need the placeholder X to bring them to 6 characters before adding the 7th. Wrong or missing 7th character is the #1 cause of injury claim denials.
Medicare LCD Coverage for T40.416
Local Coverage Determinations (LCDs) from CMS MACs that list T40.416 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing T40.416.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but T40.416 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with T40.416
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To T40.416
Other codes in section T36-T50 (Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances).
ICD-10 T40.416, Billing FAQ
Is ICD-10 code T40.416 billable? +
No, T40.416 is a non-billable header code. Use a more specific child code from block T40 when submitting claims.
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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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