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T45.4X6A

T45.4X6AUnderdosing of iron and its compounds, initial encounter

Billable / specific codeICD-10-CM

T45.4X6A is a billable, specific ICD-10-CM code for underdosing of iron and its compounds, initial encounter. It is valid for submission on a claim.

7th character "A" — initial encounter

The appropriate 7th character is to be added to each code from category T45

A
initial encounter
D
subsequent encounter
S
sequela

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

Excludes1 inherited from the categories above T45.4X6A

These are not written on T45.4X6A, but they bind it: a note on a category applies to every code beneath it. Billing T45.4X6A with anything listed here is a denial.

Written on T45.4X6 Underdosing of iron and its compounds

Risk adjustment

T45.4X6A does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

T45.4X6A is named in 2 Medicare coverage policies 2 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A57473Billing and Coding: Allergy Testing
  • A57473Billing and Coding: Allergy Testing

Code history

T45.4X6A has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share T45.4X6. If T45.4X6A is not quite right, the correct code is usually one of these.

Questions about T45.4X6A

Is T45.4X6A a billable ICD-10-CM code?
Yes. T45.4X6A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does T45.4X6A sit in the tabular list?
Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).
What cannot be coded together with T45.4X6A?
T45.4X6A carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above T45.4X6A (T45.4X6) and apply to it just the same.
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.