2022 ICD-10-CM Code T45.3X6D

Underdosing of enzymes, subsequent encounter

Version 2021

Valid for Submission

ICD-10:T45.3X6D
Short Description:Underdosing of enzymes, subsequent encounter
Long Description:Underdosing of enzymes, subsequent encounter

Code Classification

  • Injury, poisoning and certain other consequences of external causes (S00–T98)
    • Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances (T36-T50)
      • Primarily systemic and hematological agents, NEC (T45)

T45.3X6D is a billable diagnosis code used to specify a medical diagnosis of underdosing of enzymes, subsequent encounter. The code T45.3X6D is valid during the fiscal year 2022 from October 01, 2021 through September 30, 2022 for the submission of HIPAA-covered transactions. The code is exempt from present on admission (POA) reporting for inpatient admissions to general acute care hospitals.

The code T45.3X6D describes a circumstance which influences the patient's health status but not a current illness or injury. The code is unacceptable as a principal diagnosis.

T45.3X6D is a subsequent encounter code, includes a 7th character and should be used after the patient has completed active treatment for a condition like underdosing of enzymes. According to ICD-10-CM Guidelines a "subsequent encounter" occurs when the patient is receiving routine care for the condition during the healing or recovery phase of treatment. Subsequent diagnosis codes are appropriate during the recovery phase, no matter how many times the patient has seen the provider for this condition. If the provider needs to adjust the patient's care plan due to a setback or other complication, the encounter becomes active again.

Coding Guidelines

Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded.

The appropriate 7th character is to be added to each code from block Primarily systemic and hematological agents, NEC (T45). Use the following options for the aplicable episode of care:

Code Edits

The Medicare Code Editor (MCE) detects and reports errors in the coding of claims data. The following ICD-10 Code Edits are applicable to this code:

Present on Admission (POA)

T45.3X6D is exempt from POA reporting - The Present on Admission (POA) indicator is used for diagnosis codes included in claims involving inpatient admissions to general acute care hospitals. POA indicators must be reported to CMS on each claim to facilitate the grouping of diagnoses codes into the proper Diagnostic Related Groups (DRG). CMS publishes a listing of specific diagnosis codes that are exempt from the POA reporting requirement. Review other POA exempt codes here.

CMS POA Indicator Options and Definitions
POA Indicator CodePOA Reason for CodeCMS will pay the CC/MCC DRG?
YDiagnosis was present at time of inpatient admission.YES
NDiagnosis was not present at time of inpatient admission.NO
UDocumentation insufficient to determine if the condition was present at the time of inpatient admission.NO
WClinically undetermined - unable to clinically determine whether the condition was present at the time of inpatient admission.YES
1Unreported/Not used - Exempt from POA reporting. NO

Convert T45.3X6D to ICD-9 Code

Information for Patients


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Code History

  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016 (First year ICD-10-CM implemented into the HIPAA code set)