2021 ICD-10-CM Code R51.9

Headache, unspecified

Version 2021
Billable Code
New Code
No Valid Principal Dx
Unspecified Code
MS-DRG Mapping

Valid for Submission

R51.9 is a billable diagnosis code used to specify a medical diagnosis of headache, unspecified. The code R51.9 is valid during the fiscal year 2021 from October 01, 2020 through September 30, 2021 for the submission of HIPAA-covered transactions.

The ICD-10-CM code R51.9 might also be used to specify conditions or terms like aching headache, acute headache, acute pain in face, aural headache, bilateral headache , c/o - a headache, etc.

Unspecified diagnosis codes like R51.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

According to ICD-10-CM guidelines this code should not to be used as a principal diagnosis code when a related definitive diagnosis has been established.

ICD-10:R51.9
Short Description:Headache, unspecified
Long Description:Headache, unspecified

Code Classification

New 2021 ICD-10 Code

R51.9 is new to ICD-10 code set for the FY 2021, effective October 1, 2020. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2020. This is a new and revised code for the FY 2021 (October 1, 2020 - September 30, 2021).

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code R51.9:


Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code R51.9 are found in the index:

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

Clinical Information

Replacement Code

R519 replaces the following previously assigned ICD-10 code(s):

Code History

  • FY 2021 - Code Added, effective from 10/1/2020 through 9/30/2021