Substance Use ICD-10 Codes: How F10 to F19 Work

Within each substance category the fourth character names the pattern of use: 1 is abuse, 2 is dependence, and 9 is use, unspecified. The fifth character then adds detail: 0 is uncomplicated and 1 is in remission, while 2 to 9 describe intoxication, withdrawal and substance-induced disorders. Some of those carry a sixth character. Alcohol shows the full pattern, and the other substances follow it with some characters left out.

Each pattern carries Excludes1 notes for the other two. For example, F10.1 Alcohol abuse excludes alcohol dependence (F10.2-) and alcohol use, unspecified (F10.9-). Excludes1 means the codes are never reported together for the same substance, unless the conditions are unrelated (Official Guidelines Section I.A.12.a).

The same structure repeats across the other categories. These are the uncomplicated and in-remission codes clinicians use most often, with their official FY2027 descriptions:

The FY2027 Alphabetic Index lists alcohol, opioid, cannabis, cocaine, hallucinogen and inhalant use disorders by severity. "Disorder, alcohol use, mild" is indexed to F10.10 and "moderate or severe" to F10.20; the same pattern holds for the other five substances (for example F11.10 and F11.20 for opioids). The in-remission entries follow suit: mild goes to the abuse in remission code (F10.11) and moderate or severe to the dependence in remission code (F10.21).

The Official Guidelines say the same in their Chapter 5 section: mild substance use disorders in early or sustained remission are classified to the codes for substance abuse in remission, and moderate or severe ones to the codes for substance dependence in remission (Section I.C.5.b.1). Remission codes require the provider's clinical judgment and are assigned only on the basis of provider documentation.

The Official Guidelines give a hierarchy for one substance (Section I.C.5.b.2): if both use and abuse are documented, assign only the code for abuse; if both abuse and dependence are documented, assign only the code for dependence; if use, abuse and dependence are all documented, assign only dependence; and if both use and dependence are documented, assign only dependence.

This hierarchy applies to the same substance. A client with alcohol dependence and cannabis abuse has one code for each substance. When the provider documents use of a substance with no disorder, the Guidelines add that the use, unspecified codes (F10.9-, F11.9-, F12.9-, F13.9-, F14.9-, F15.9- and so on) may be assigned only when the substance use is associated with a substance-related disorder or medical condition and the provider documents that relationship (Section I.C.5.b.3).

The Guidelines say medical conditions due to substance use, abuse and dependence are not classified as substance-induced disorders. The medical condition is coded as directed by the Alphabetic Index, together with the appropriate use, abuse or dependence code (Section I.C.5.b.4). Their example is alcoholic pancreatitis in a client with alcohol dependence, which takes a pancreatitis code and F10.20, not F10.288.

Category F10 has a "use additional code" note for blood alcohol level, if applicable (Y90.-). Y90 is the category Evidence of alcohol involvement determined by blood alcohol level. The Official Guidelines say a Y90 code may be assigned when the blood alcohol level is documented and the provider has documented a condition classifiable to category F10 (Section I.C.5.b.5).

The ICD-10-CM code says why the client is being seen; the CPT code says what service was provided. A 53 minute individual session for a client with documented alcohol dependence is reported as CPT 90837 with F10.20 as the diagnosis, and group sessions are reported with CPT 90853. Which diagnoses, services and settings a payer covers for substance use treatment varies by payer and by plan. Confirm with the payer before billing.