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ICD-10-CM 2027

ICD-10 code for Sirolimus long-term drug therapy

Z79.623

Long term (current) use of mammalian target of rapamycin (mTOR) inhibitor

✓ Billable / specificNot a principal dx

From the official ICD-10-CM alphabetic index entry “Long-term (current) (prophylactic) drug therapy (use of) › sirolimus”. Page updated September 29, 2026.

About coding Sirolimus long-term drug therapy

The ICD-10-CM code for Sirolimus long-term drug therapy is Z79.623 (Long term (current) use of mammalian target of rapamycin (mTOR) inhibitor).

Within Z79.62 (long term (current) use of immunosuppressant), Z79.623 is specifically for long term (current) use of mammalian target of rapamycin (mTOR) inhibitor. Related codes cover immunosuppressive biologic (Z79.620), calcineurin inhibitor (Z79.621), Janus kinase inhibitor (Z79.622) and inhibitors of nucleotide synthesis (Z79.624).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 949 (Aftercare with CC/MCC, relative weight 1.123) and DRG 950 (Aftercare without CC/MCC, relative weight 0.7664), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

Common questions about Sirolimus long-term drug therapy ICD-10 codes

What is the ICD-10 code for Sirolimus long-term drug therapy?

Z79.623 — Long term (current) use of mammalian target of rapamycin (mTOR) inhibitor.

Is Z79.623 billable?

Yes. Z79.623 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Z79.623 be used as a principal diagnosis?

No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.

Is Z79.623 a CC or MCC?

No. Z79.623 is neither a CC nor an MCC under MS-DRG v44.0.