Z79.64 Long term (current) use of myelosuppressive agent
Billable ICD-10-CM code, FY2026. Exempt from present-on-admission (POA) reporting.
Applicable to
Long term (current) use of hydroxyurea
Applies from Z79 Long term (current) drug therapy
Includes
long term (current) drug use for prophylactic purposes
Excludes2 (not included here)
drug abuse and dependence (F11-F19)
drug use complicating pregnancy, childbirth, and the puerperium (O99.32-)
Code also
any therapeutic drug level monitoring (Z51.81)
Applies from Z79.6 Long term (current) use of immunomodulators and immunosuppressants
Excludes2 (not included here)
long term (current) use of steroids (Z79.5-)
long term (current) use of agents affecting estrogen receptors and estrogen levels (Z79.81-)
MS-DRG index
Defines the logic of DRG(s) 949-950 in MDC 23.
Medicare Code Edits (MCE v43.1 (April 2026))
Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.
Code annotations containing back-references to Z79.64
Back-references to Z79
Code Also: Z51.81 Encounter for therapeutic drug level monitoring ("any long-term (current) drug therapy (Z79.-)")
Type 2 Excludes: Z92.2 Personal history of drug therapy ("long term (current) drug therapy (Z79.-)")
Diagnosis Index entries for Z79.64
Long-term (current) (prophylactic) drug therapy (use of) › hydroxyurea
Long-term (current) (prophylactic) drug therapy (use of) › myelosuppressive agent
Nearby codes
Z79.630 Long term (current) use of alkylating agent
Z79.631 Long term (current) use of antimetabolite agent
Z79.632 Long term (current) use of antitumor antibiotic
Z79.633 Long term (current) use of mitotic inhibitor
Z79.634 Long term (current) use of topoisomerase inhibitor
Z79.64 Long term (current) use of myelosuppressive agent (this code)
Z79.69 Long term (current) use of other immunomodulators and immunosuppressants