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T36.4X5A

T36.4X5AAdverse effect of tetracyclines, initial encounter

Billable / specific codeICD-10-CM

T36.4X5A is a billable, specific ICD-10-CM code for adverse effect of tetracyclines, 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 T36

A
initial encounter
D
subsequent encounter
S
sequela

Risk adjustment

T36.4X5A 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

T36.4X5A is named in 27 Medicare coverage policies 27 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A56538Billing and Coding: Allergen Immunotherapy
  • A56558Billing and Coding: Allergy Testing
  • A56558Billing and Coding: Allergy Testing
  • A56844Billing and Coding: RAST Type Tests

Related codes at this level

Codes that share T36.4X5. If T36.4X5A is not quite right, the correct code is usually one of these.

Questions about T36.4X5A

Is T36.4X5A a billable ICD-10-CM code?
Yes. T36.4X5A is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does T36.4X5A 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).
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.