ICD-10-CM 2027
ICD-10 code for fever newborn
From the official ICD-10-CM alphabetic index entry “Newborn (infant) (liveborn) (singleton) › fever”. Page updated September 29, 2026.
About coding fever newborn
The ICD-10-CM code for fever newborn is P81.9 (Disturbance of temperature regulation of newborn, unspecified). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on P81.9.
Within P81, choose P81.9 (Disturbance of temperature regulation of newborn, unspecified) only when documentation doesn't support a more specific option: environmental hyperthermia of newborn (P81.0) and other specified disturbances of temperature regulation of newborn (P81.8).
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 794 (Neonate with Other Significant Problems, relative weight 1.4935), in MDC 15 (Newborns and Other Neonates with Conditions Originating in the Perinatal Period), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific fever newborn codes (official index)
- environmentally-induced P81.0 — Environmental hyperthermia of newborn
Common questions about fever newborn ICD-10 codes
What is the ICD-10 code for fever newborn?
- P81.9 — Disturbance of temperature regulation of newborn, unspecified. More specific codes apply when the documentation supports them: P81.0.
What is the ICD-10 code for environmentally-induced fever newborn?
- P81.0 — Environmental hyperthermia of newborn.
Is P81.9 billable?
- Yes. P81.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can P81.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict P81.9 as a principal diagnosis.
Is P81.9 a CC or MCC?
- No. P81.9 is neither a CC nor an MCC under MS-DRG v44.0.