F11.20 & ICD-10 F11 Opioid Codes: Complete

F11.20 — opioid dependence, uncomplicated — is the single most-billed diagnosis code at many opioid treatment programs and SUD facilities. It is also one of the most-audited, because it sits at the intersection of three things payers scrutinize: high-cost levels of care, medication-assisted treatment, and remission documentation. This guide covers the full F11 family in the FY2026 code set: every billable code, the stem and specifier logic, the MAT coding questions no scribe-tool code page touches, and the billing rules by level of care.

All codes and titles are verified against the FY2026 ICD-10-CM code set (effective October 1, 2025) from CDC/NCHS ↗ and CMS ↗; rules cite the ICD-10-CM Official Guidelines FY2026 ↗, Section I.C.5.b. Part of the ICD-10 behavioral health directory.

F11 at a glance

Category F11, Opioid related disorders, follows the standard substance-family template — three stems, then specifiers:

DSM-5-TR frames everything as one opioid use disorder (OUD) with a severity grade; ICD-10-CM still splits abuse from dependence. The FY2026 tabular’s inclusion terms bridge the two:

“Opioid” covers the full pharmacological class — heroin, prescription analgesics (oxycodone, hydrocodone, fentanyl ), and synthetic opioids. The drug’s legal status doesn’t change the code family; the documented relationship to the substance does.

• Mild OUD → F11.10 (opioid abuse, uncomplicated)
• Moderate or severe OUD → F11.20 (opioid dependence, uncomplicated)
• In remission: mild → F11.11; moderate/severe → F11.21 (early and sustained remission share one code)

Complete F11 code table (FY2026)

All codes below are valid, billable FY2026 codes. Note two structural quirks versus the F10 alcohol family: opioid withdrawal codes are single 5th-character codes (F11.13, F11.23, F11.93 — no delirium/perceptual-disturbance split), and opioid intoxication adds a perceptual-disturbance option (6th character 2). There are also no anxiety-disorder or amnestic/dementia specifiers in F11.

F11.1- — Opioid abuse

F11.2- — Opioid dependence

F11.9- — Opioid use, unspecified

Per Official Guidelines I.C.5.b.3, F11.9- codes require provider documentation and a documented link between the opioid use and a related disorder or medical condition — they are not a catch-all for “patient takes opioids.”

F11.20 deep dive

Why F11.20 deserves its own section: it is the diagnosis that anchors OTP weekly bundles, office-based buprenorphine treatment, and residential opioid claims — and the most common place coding and utilization review collide.

When F11.20 applies: the provider documents opioid dependence (or moderate/severe OUD), and the patient is not in documented withdrawal and has no documented opioid-induced disorder. “Uncomplicated” describes the coding picture, not the patient — a patient with severe OUD stabilizing on buprenorphine is still F11.20 if no withdrawal or induced disorder is documented at the encounter.

F11.20 vs its neighbors:

• F11.23 — active withdrawal documented (COWS scores, withdrawal protocol). Use during induction/detox phases where withdrawal is being managed.
• F11.21 — provider has documented remission. The switch from F11.20 to F11.21 should be a deliberate, documented clinical decision, not a billing default.
• F11.10 — mild OUD. Rare as a facility-level principal diagnosis; payers question abuse-stem codes attached to dependence-level services.

The hierarchy and remission rules, applied to opioids

The two Official Guidelines rules that resolve most F11 stem questions:

Hierarchy (I.C.5.b.2). One substance, one code. If the chart documents both opioid use and abuse → code abuse; abuse and dependence → dependence; use and dependence → dependence; all three → dependence. An H&P that says “opiate abuse” plus a psych eval documenting “opioid dependence” is coded once, to F11.2-.

Remission (I.C.5.b.1). Remission codes are assigned only on provider documentation. The severity bridge carries over: mild OUD in early or sustained remission → F11.11; moderate or severe → F11.21. ICD-10-CM does not distinguish early from sustained remission at the code level — that nuance lives in the note.

These rules apply per substance: a patient with opioid dependence and cocaine abuse carries one F11.2- code and one F14.1- code together.

Coding OUD on medication-assisted treatment

This is the section that matters most to OTPs and MAT programs — and the one competitor code pages skip entirely.

The core question: a patient stable on methadone or buprenorphine for two years — dependent, or in remission? ICD-10-CM does not decide this; the provider does. Both of these are defensible when documented:

What a coder may not do is infer either state from the medication list. MAT participation is treatment, not remission evidence; conversely, years of negative screens don’t authorize a coder to “upgrade” to remission without a provider statement. Facilities should set a documentation policy so providers address remission status explicitly at treatment-plan reviews.

What about Z79.891? Z79.891 is long term (current) use of opiate analgesic — it exists for patients on long-term opioid analgesic therapy (e.g., chronic pain management), not as a substitute diagnosis for OUD treated with medication. When the provider documents OUD, the F11 code carries the claim.

OTP billing connection: Medicare pays Opioid Treatment Programs through weekly bundled G-codes — G2067 (methadone weekly bundle), G2068 (buprenorphine oral), through G2080 (additional counseling add-on) — described on CMS’s OTP billing pages ↗. The diagnosis supporting those bundles is the documented OUD — in practice F11.2x (or F11.21 with documented remission and continued medication need). An OTP claim whose diagnosis and bundle disagree — or whose remission documentation evaporated three treatment-plan reviews ago — is audit bait.

Clinical grounding for MAT itself: SAMHSA ’s TIP 63, Medications for Opioid Use Disorder (see the methadone chapter on NCBI Bookshelf ↗ ).

is the EHR/RCM layer for OTPs: G-code and episode-based billing for bundles like G2067–G2080 is supported on the RCM side, while native dosing and dispensing tooling is on our roadmap — today we integrate with established dispensing systems.

• Provider documents active opioid dependence, managed with methadone maintenance → F11.2x
• Provider documents moderate/severe OUD in sustained remission, on buprenorphine maintenance → F11.21

Opioid withdrawal coding (F11.23, F11.13, F11.93)

Opioid withdrawal gets one code per stem — F11.23 (dependence), F11.13 (abuse), F11.93 (unspecified use) — with no 6th-character delirium or perceptual-disturbance options, unlike alcohol or sedatives.

Documentation that supports a withdrawal code: provider diagnosis of opioid withdrawal, serial severity scores (COWS — Clinical Opiate Withdrawal Scale — is the standard instrument), time since last use, and the management protocol (comfort medications, buprenorphine induction timing). During buprenorphine induction, documented withdrawal before first dose is precisely what F11.23 captures — and it supports the withdrawal-management or induction service billed (e.g., H0010, H0014, or OTP intake H0001 depending on setting and payer).

Documentation requirements and chart shorthand

Per code group, the record needs: a provider diagnostic statement naming the substance and pattern (or DSM severity); for remission codes, an explicit remission statement; for withdrawal, the withdrawal diagnosis plus clinical corroboration; for induced disorders, both the induced condition and the causal attribution (“opioid-induced depressive disorder”) in the provider’s words.

Medical necessity and billing by level of care

The recurring audit themes mirror the alcohol family: abuse-stem codes on dependence-level claims, remission codes that contradict the requested intensity, and unspecified codes where the chart supports specificity. See denial codes in addiction treatment billing for the downstream CARC/RARC patterns, and behavioral health RCM for fixing them systemically.

Treatment planning for opioid-related diagnoses

Treatment plans for F11 diagnoses almost always have a medication dimension, which makes the diagnosis-plan linkage tighter than for any other family: the plan should state the documented diagnosis (F11.20 vs F11.21 changes the goal structure), the MOUD regimen and its monitoring objectives, counseling intensity, and overdose-prevention planning (naloxone education belongs in nearly every opioid treatment plan).

A fictional example: a 29-year-old admitted for buprenorphine induction with F11.23 (dependence with withdrawal); after stabilization the working diagnosis returns to F11.20, with plan goals of medication adherence, 3× weekly IOP attendance ( H0015 ), and employment re-engagement; at month nine the provider documents severe OUD in sustained remission on maintenance — F11.21 — and the plan steps to monthly recovery-maintenance visits.

Structure and examples in our treatment plan guide; plain-language background at the opioid use disorder glossary entry.

More ICD-10 resources

Codes verified against the FY2026 ICD-10-CM tabular list (effective October 1, 2025). Reviewed against each annual ICD-10-CM update.

From COWS score to clean claim: ’s EHR ties diagnosis, MAT documentation, and billing together for opioid treatment providers — request a demo.

Reference tables

Common questions

Official sources

• CDC/NCHScdc.gov
• CMScms.gov
• ICD-10-CM Official Guidelines FY2026ftp.cdc.gov
• CMS’s OTP billing pagescms.gov
• methadone chapter on NCBI Bookshelfncbi.nlm.nih.gov