Z51.81 Encounter for therapeutic drug level monitoring

Coding notes

From the ICD-10-CM FY2027 (effective October 1, 2026) tabular list. Notes on a parent code or category apply here too.

Excludes1

Not coded together with this code. The exception is when the two conditions are unrelated to each other.

• encounter for blood-drug test for administrative or medicolegal reasons (Z02.83)
• holiday relief care (Z75.5)
• follow-up examination after treatment (Z08-Z09)

Excludes2

Not part of this code, but both can be coded when both are documented.

• follow-up examination for medical surveillance after treatment (Z08-Z09)

Code also

A second code may be needed. Sequencing depends on the encounter.

• any long-term (current) drug therapy (Z79.-)
• condition requiring care