Z51.81 - Encounter for therapeutic drug level monitoring

Version 2023
Billable Code
MS-DRG Mapping
POA Exempt
Convert to ICD-9
ICD-10:Z51.81
Short Description:Encounter for therapeutic drug level monitoring
Long Description:Encounter for therapeutic drug level monitoring
Status: Valid for Submission
Version:ICD-10-CM 2023
Code Classification:
  • Factors influencing health status and contact with health services (Z00–Z99)
    • Encounters for other specific health care (Z40-Z53)
      • Encounter for other aftercare and medical care (Z51)

Z51.81 is a billable ICD-10 code used to specify a medical diagnosis of encounter for therapeutic drug level monitoring. The code is valid during the fiscal year 2023 from October 01, 2022 through September 30, 2023 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.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more. The following references are applicable to this diagnosis code:


Code Also

Code Also
A "code also" note instructs that two codes may be required to fully describe a condition, but this note does not provide sequencing direction.

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

Index to Diseases and Injuries References

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for this diagnosis code are found in the injuries and diseases index:

Present on Admission (POA)

Z51.81 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 to ICD-9 Code

Source ICD-10 CodeTarget ICD-9 Code
Z51.81V58.83 - Therapeutic drug monitor

Code History

Previous Code: Z51.8

Parent Code: Z51.8

Next Code: Z51.89