T45.AX6A — Underdosing of immune checkpoint inhibitors and immunostimulant drugs, initial encounter
Is T45.AX6A billable?
Yes — T45.AX6A is billable for FY2027. T45.AX6A is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. T45.AX6A may be submitted for encounters from October 1, 2026 through September 30, 2027.
T45.AX6A at a glance
| Code | T45.AX6A |
|---|---|
| Description | Underdosing of immune checkpoint inhibitors and immunostimulant drugs, initial encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter |
What does the 7th character "A" mean in T45.AX6A?
In T45.AX6A, the 7th character A means initial encounter. The 7th character is required for T45.AX6A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
Which MS-DRGs does T45.AX6A group to?
T45.AX6A sits in MDC 23 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 951Other Factors Influencing Health Statusmedical
Excludes1 — never code together — inherited from T36-T50
The conditions below can never be reported together with T45.AX6A on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- toxic reaction to local anesthesia in pregnancy (O29.3-)
Excludes1 — never code together — inherited from T45.A
The conditions below can never be reported together with T45.AX6A on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drug (T45.1)
Code first — inherited from T36-T50
The underlying condition below must be sequenced before T45.AX6A. T45.AX6A describes a manifestation and cannot be the principal or first-listed diagnosis.
Use additional code — inherited from Chapter 19
Report an additional code alongside T45.AX6A to fully describe the condition. T45.AX6A is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Use additional code — inherited from T36-T50
Report an additional code alongside T45.AX6A to fully describe the condition. T45.AX6A is sequenced first.
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T45.AX6A, but a patient may have both at the same time. When documentation supports it, T45.AX6A and the excluded code may both be reported.
Excludes2 — not included here — inherited from T36-T50
The conditions below are not part of T45.AX6A, but a patient may have both at the same time. When documentation supports it, T45.AX6A and the excluded code may both be reported.
How long has T45.AX6A existed?
T45.AX6A first appears in FY2025.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.