2025 ICD-10-CM Diagnosis Code M46.1

Sacroiliitis, not elsewhere classified

ICD-10-CM Code:
M46.1
ICD-10 Code for:
Sacroiliitis, not elsewhere classified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Chronic
Code Navigator:

M46.1 is a billable diagnosis code used to specify a medical diagnosis of sacroiliitis, not elsewhere classified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.

Code Classification

  • Diseases of the musculoskeletal system and connective tissue
    M00–M99
    • Spondylopathies
      M45-M49
      • Other inflammatory spondylopathies
        M46

Approximate Synonyms

The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.

  • Bilateral sacroiliitis
  • Inflammation of sacroiliac joint
  • Sacroiliitis of left sacroiliac joint
  • Sacroiliitis of right sacroiliac joint

Clinical Classification

Clinical Classifications group individual ICD-10-CM diagnosis codes into broader, clinically meaningful categories. These categories help simplify complex data by organizing related conditions under common clinical themes.

They are especially useful for data analysis, reporting, and clinical decision-making. Even when diagnosis codes differ, similar conditions can be grouped together based on their clinical relevance. Each category is assigned a unique CCSR code that represents a specific clinical concept, often tied to a body system or medical specialty.

Spondylopathies/spondyloarthropathy (including infective)

CCSR Code: MUS011

Inpatient Default: Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.

Outpatient Default: Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Convert M46.1 to ICD-9-CM

Below are the ICD-9 codes that most closely match this ICD-10 code, based on the General Equivalence Mappings (GEMs). This ICD-10 to ICD-9 crosswalk tool is helpful for coders who need to reference legacy diagnosis codes for audits, historical claims, or approximate code comparisons.

Sacroiliitis NEC

ICD-9-CM: 720.2

This is a direct match with no additional mapping qualifiers. The absence of a flag generally means the mapping is considered exact or precise. In other words, the ICD-10 code maps cleanly to the ICD-9 code without qualification, approximation, or needing multiple codes.

Patient Education


Back Pain

If you've ever groaned, "Oh, my aching back!", you are not alone. Back pain is one of the most common medical problems, affecting 8 out of 10 people at some point during their lives. Back pain can range from a dull, constant ache to a sudden, sharp pain. Acute back pain comes on suddenly and usually lasts from a few days to a few weeks. Back pain is called chronic if it lasts for more than three months.

Most back pain goes away on its own, though it may take awhile. Taking over-the-counter pain relievers and resting can help. However, staying in bed for more than 1 or 2 days can make it worse.

If your back pain is severe or doesn't improve after three days, you should call your health care provider. You should also get medical attention if you have back pain following an injury.

Treatment for back pain depends on what kind of pain you have, and what is causing it. It may include hot or cold packs, exercise, medicines, injections, complementary treatments, and sometimes surgery.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases


[Learn More in MedlinePlus]

Back Pain

Back pain is one of the most common medical problems in the United States. It might feel like a dull, constant ache or a sudden, sharp pain.
[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.