ICDcodes.org
FY2027

T45.526AUnderdosing of antithrombotic drugs, initial encounter

Billable

Is T45.526A billable?

Yes — T45.526A is billable for FY2027. T45.526A is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. T45.526A may be submitted for encounters from October 1, 2026 through September 30, 2027.

T45.526A at a glance

CodeT45.526A
DescriptionUnderdosing of antithrombotic drugs, initial encounter
BillableYes
Code setICD-10-CM FY2027
Valid for encountersOctober 1, 2026 – September 30, 2027
7th character "A"initial encounter

What does the 7th character "A" mean in T45.526A?

In T45.526A, the 7th character A means initial encounter. The 7th character is required for T45.526A to be a valid, complete code.

Same condition, different episode of care — switch the 7th character:

What Medicare edits apply to T45.526A?

The Medicare Code Editor screens inpatient claims before they are grouped. These edits name T45.526A directly.

Cannot be a principal diagnosis — MCE edit 9

CMS will reject this code as the principal diagnosis on an inpatient claim. It describes something other than the condition chiefly responsible for the admission.

Which MS-DRGs does T45.526A group to?

T45.526A 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 T45.526A 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-)

Code first — inherited from T36-T50

The underlying condition below must be sequenced before T45.526A. T45.526A describes a manifestation and cannot be the principal or first-listed diagnosis.

  • , for adverse effects, the nature of the adverse effect, such as:
  • adverse effect NOS (T88.7)
  • aspirin gastritis (K29.-)
  • blood disorders (D56-D76)
  • contact dermatitis (L23-L25)
  • dermatitis due to substances taken internally (L27.-)
  • nephropathy (N14.0-N14.2)

Use additional code — inherited from Chapter 19

Report an additional code alongside T45.526A to fully describe the condition. T45.526A 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 T45.526A to fully describe the condition. T45.526A is sequenced first.

  • code(s) to specify:
  • manifestations of poisoning
  • underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
  • underdosing of medication regimen (Z91.12-, Z91.13-)

Excludes2 — not included here — inherited from Chapter 19

The conditions below are not part of T45.526A, but a patient may have both at the same time. When documentation supports it, T45.526A and the excluded code may both be reported.

  • birth trauma (P10-P15)
  • obstetric trauma (O70-O71)

Excludes2 — not included here — inherited from T36-T50

The conditions below are not part of T45.526A, but a patient may have both at the same time. When documentation supports it, T45.526A and the excluded code may both be reported.

  • abuse and dependence of psychoactive substances (F10-F19)
  • abuse of non-dependence-producing substances (F55.-)
  • immunodeficiency due to drugs (D84.821)
  • drug reaction and poisoning affecting newborn (P00-P96)
  • pathological drug intoxication (inebriation) (F10-F19)

Excludes2 — not included here — inherited from T45.52

The conditions below are not part of T45.526A, but a patient may have both at the same time. When documentation supports it, T45.526A and the excluded code may both be reported.

  • poisoning by, adverse effect of and underdosing of aspirin (T39.01-)
  • poisoning by, adverse effect of and underdosing of acetylsalicylic acid (T39.01-)

How long has T45.526A existed?

T45.526A has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.