Is ICD-10-CM code Z79 billable?

No, Z79 (Long term (current) drug therapy) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code Z79 belong to?

Z79 belongs to Chapter 21 of the ICD-10-CM tabular list: Z00–Z99 (Factors Influencing Health Status and Contact with Health Services).

Z79Not billable, use a more specific code below

Long term (current) drug therapy

In Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99), chapter 21: Factors Influencing Health Status and Contact with Health Services

32 billable codes under Z79: none are a CC or MCC; 1 map to HCC 38 (Diabetes with Glycemic, Unspecified, or No Complications).An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

long term (current) drug use for prophylactic purposes

Excludes2: not included here, code separately if applicable

drug abuse and dependence (F11-F19)
drug use complicating pregnancy, childbirth, and the puerperium (O99.32-)

Code also: add a code for this too, order depends on the encounter

any therapeutic drug level monitoring (Z51.81)

Also applies, from Persons with potential health hazards related to family and personal history and certain conditions influencing health status (Z77-Z99)

These notes sit on Z77-Z99 and apply to every code under it, including Z79.

Code also: add a code for this too, order depends on the encounter

any follow-up examination (Z08-Z09)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Covers when and how to use Z codes (Z00-Z99) for encounters and supplementary information, including contact, status, history, screening, aftercare, exams, and social determinants of health.

Use of Z Codes in Any Healthcare Setting (page 92)
Z Codes Indicate a Reason for an Encounter or Provide Additional Information about a Patient Encounter (page 93)
Categories of Z Codes (page 93)

Read Section I.C.21 (page 92)

All codes under Z79

Z79 can't be used on a claim. Pick a billable code below; grey headings group them.

Z79 MS-DRGs

As the principal diagnosis, the billable codes under Z79 group to MS-DRG 949, 950, or 951 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 949 Aftercare with CC/MCC (28 of 32 codes)
DRG 950 Aftercare without CC/MCC (28 of 32 codes)
DRG 951 Other Factors Influencing Health Status (4 of 32 codes)

Other codes that refer to Z79

Notes on these codes point to Z79.

Z51.81 Code Also: any long-term (current) drug therapy (Z79.-)
Z92.2 Excludes2: long term (current) drug therapy (Z79.-)

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.