ICD-10-CM 2027
ICD-10 code for Postimmunization fever
From the official ICD-10-CM alphabetic index entry “Fever (inanition) (of unknown origin) (persistent) (with chills) (with rigor) › postimmunization”. Page updated September 29, 2026.
About coding Postimmunization fever
The ICD-10-CM code for Postimmunization fever is R50.83 (Postvaccination fever).
Within R50.8 (other specified fever), R50.83 is specifically for Postvaccination fever. Related codes cover fever presenting with conditions classified elsewhere (R50.81), postprocedural fever (R50.82) and febrile nonhemolytic transfusion reaction (R50.84).
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 864 (Fever and Inflammatory Conditions, relative weight 0.8551), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), 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 Postimmunization fever ICD-10 codes
What is the ICD-10 code for Postimmunization fever?
- R50.83 — Postvaccination fever.
Is R50.83 billable?
- Yes. R50.83 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R50.83 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R50.83 as a principal diagnosis.
Is R50.83 a CC or MCC?
- No. R50.83 is neither a CC nor an MCC under MS-DRG v44.0.