PTSD ICD-10 Codes: F43.10, F43.11, and F43.12

A client describes a car accident, nightmares, and months of avoiding the freeway. The claim goes out with F43.1 because that is the code the therapist remembers for PTSD. The claim rejects. F43.1 is the family name. It is not a code you can bill.

PTSD ICD-10 coding comes down to three billable codes, and the difference between them is duration. Get the duration into the note and the code choice is straightforward. Leave it out and you are stuck with an unspecified code that payers eventually question.

The FY2027 ICD-10-CM set took effect October 1, 2026.^[1] Chapter 5, which includes the F43 stress codes, had no new, revised, or deleted codes in that update.^[2]

Three Billable PTSD Codes

F43.1 is the header for post-traumatic stress disorder. You need a fifth character.^[3]

All three are billable. F43.12 is the code most ongoing therapy should land on once you know the symptoms have lasted three months or longer. F43.11 is the early window. F43.10 is what you use when the diagnosis is PTSD and the record does not say how long.

ICD-10-CM's three-month line is not the same cut point as DSM-5-TR. DSM-5-TR PTSD requires more than one month of symptoms. A client can meet DSM criteria and still be F43.11 if you are inside the first three months. After three months, update the claim to F43.12. Leaving F43.10 on a client you have seen all year tells the payer you never documented duration.

Do Not Confuse PTSD With the Codes Next Door

Several F43 codes sit beside PTSD and get selected by accident.

F43.0, acute stress reaction, is the immediate reaction to exceptional stress. It is not the code for PTSD that started last month. Acute stress reaction is short. If you are three weeks out from a trauma and the presentation is an acute stress picture rather than PTSD, F43.0 may be the honest code. If the clinician has diagnosed PTSD and duration is under three months, use F43.11.

Adjustment disorder lives in F43.2. A divorce, a layoff, or a move can be deeply destabilizing and still not be PTSD. PTSD coding assumes a traumatic stressor of the kind the diagnosis requires. Job loss coded as F43.12 will not match the note, and it can create trouble if the record is reviewed. Adjustment disorder has its own subtypes. Use those when that is the diagnosis.

Personal history of trauma is not active PTSD. Codes in Z91.4-, personal history of psychological trauma, describe history. They do not replace F43.12 for a client in treatment now. History codes also do not, by themselves, establish medical necessity for weekly psychotherapy.

Complex PTSD has an ICD-11 code. It does not have its own ICD-10-CM code. When the diagnosis is chronic PTSD, use F43.12. When the clinician has diagnosed another reaction to severe stress, and PTSD criteria are not met, the billable code is F43.89.^[4] F43.8, the old header, will not pay. Do not invent a fifth digit for "complex," and do not put a non-PTSD stress reaction on F43.12 because that is the familiar code.

Sequence PTSD With the Other Diagnoses You Treat

PTSD often shows up with depression, anxiety, or a substance use disorder. Code the conditions that affect this episode of care. A trauma-focused course with depression in the background may list F43.12 first and the depression code second. A session that is entirely about a current major depressive episode, with PTSD stable, may flip that order.

Substance use needs its own code from F10-F19. Do not bury alcohol dependence inside the PTSD code. Payers, and your own treatment plan, need both. If the client is in a trauma group and an individual session on the same day, the CPT rules for same-day services still apply. The diagnosis does not override them.

A Duluth practice treating a veteran with chronic PTSD and alcohol dependence in early remission might send F43.12 and F10.21. Both codes should appear in the assessment, not only on the claim. If the note says "history of drinking" and the claim says dependence in remission, you have a documentation gap. Remission codes require the clinician's statement.^[5]

Community programs add another layer. An ARMHS provider in Minneapolis may list PTSD as the diagnosis and still bill a rehabilitative HCPCS code rather than 90837. The diagnosis supports medical necessity. The procedure code has to match the service. Medicaid mental health billing is where those program rules live.

What Payers Push Back On

Unspecified PTSD on a long-term client is the pattern we see most. PTSD ICD-10 claims that stay on F43.10 after the duration is known are the ones that draw record requests. F43.10 at intake is reasonable. F43.10 on visit 20 usually means the duration never made it into the diagnosis field. Update the code when you update the plan.

The other pushbacks are familiar:

• F43.1 submitted as if it were billable
• PTSD on the claim and a note that describes ordinary stress, with no traumatic event and no symptom cluster
• A treatment plan that requests more sessions while the only diagnosis is a history Z code
• Authorization packets that say chronic PTSD while the claim still says F43.10

Medicare's outpatient psychotherapy articles list specific PTSD codes, including F43.11 and F43.12, among the diagnoses that support psychotherapy.^[6] Coverage still depends on the local policy, the CPT code, and the record. A listed diagnosis is not a promise of payment.

When denials mention medical necessity, pull the note before you change the code to something "stronger." Upcoding duration you did not assess will not survive a review. Denial tracking helps you see whether one payer is pending F43.10, or whether the problem is authorization.

A weak clean claim rate on trauma claims is a signal to check the fifth digit and the auth along with the narrative.

Keep Duration in the Diagnosis, Not Only the Narrative

The narrative often has the timeline. The diagnosis line does not. Add one field to the assessment: symptom duration under 3 months, 3 months or more, or not yet known. That field maps to F43.11, F43.12, or F43.10.

BreezyBilling will not pick a clinical code for you. We will notice when a practice's PTSD claims are all unspecified, or when a payer starts asking for notes on F43.10 after the twelfth visit. A monthly review with your coordinator is the right place to catch that, while the charts can still be updated.

If you are writing a trauma protocol for a group practice in Illinois or Minnesota, decide the code path before the first auth. Intake can be F43.10. The second or third session should be able to support F43.11 or F43.12.

Code the Duration You Already Know

PTSD ICD-10 billing uses F43.10, F43.11, and F43.12. F43.1 will not pay. Acute stress, adjustment disorder, F43.89, and a history of trauma are different codes for different clinical pictures. Once symptoms have lasted three months and the diagnosis is PTSD, F43.12 is the code the record should carry.

If PTSD claims are rejecting and you cannot tell the code from the auth problem, contact BreezyBilling. We will look at the billing pattern with you.

Sources

1. ICD-10-CM Files - CDC/NCHS
2. FY 2027 ICD-10-CM Code Updates - HIAcode, 2026
3. 2026 ICD-10-CM Diagnosis Code F43.10 - ICD10data
4. 2026 ICD-10-CM Diagnosis Code F43.89 - ICD10data
5. FY 2027 ICD-10-CM Official Guidelines for Coding and Reporting - CMS and NCHS, 2026
6. Billing and Coding: Outpatient Psychotherapy (A59723) - CMS, revised 2026