Ankylosing Spondylitis ICD-10-CM Codes

Read this short guide to learn about ankylosing spondylitis ICD codes you can use!

By Matt Olivares on Aug 8, 2025.

Ankylosing spondylitis ICD-10 codes you can use

If you're looking for ankylosing spondylitis ICD-10 codes, there's much to pick from!

The basic code you're looking for is M45.9—Ankylosing spondylitis of unspecified sites in spine. It is meant to be used on patients confirmed to have ankylosing spondylitis.

It also comes with an unspecified label, which means the specific location of the problem isn't known or identified. Once the specific body region is identified and confirmed, please use any of the more specific ICD-10 codes:

M45.1 - Ankylosing spondylitis of occipito-atlanto-axial region
M45.2 - Ankylosing spondylitis of cervical region
M45.3 - Ankylosing spondylitis of cervicothoracic region
M45.4 - Ankylosing spondylitis of thoracic region
M45.5 - Ankylosing spondylitis of thoracolumbar region
M45.6 - Ankylosing spondylitis lumbar region
M45.7 - Ankylosing spondylitis of lumbosacral region
M45.8 - Ankylosing spondylitis sacral and sacrococcygeal region

If your patient's ankylosing spondylitis has affected multiple regions, you can use M45.0 - Ankylosing spondylitis of multiple sites in spine.

Are these ankylosing spondylitis ICD-10 codes billable?

Yes. These ICD-10 codes for ankylosing spondylitis are valid and billable.

Clinical information about ankylosing spondylitis

Ankylosing spondylitis is a type of arthritis characterized by chronic spine inflammation. This condition causes the sacroiliac and vertebral joints to become inflamed, leading to persistent back and hip pain, including stiffness. The person feels pain whether they're immobile or moving their back, and they will also have difficulty moving.

Over time, the vertebrae may fuse due to new bone formations, which can further affect the spine, resulting in a stooped posture and even lessening the spine's flexibility.

Besides back pain, hip pain, and stiffness, people who have ankylosing spondylitis will likely have the following symptoms:

Neck pain
Joint pain
Abdominal pain
Weakness and fatigue
Difficulty breathing
Loss of appetite
Weight loss
Diarrhea

Synonyms include

Ankylosing spondylitis of occipito-atlanto-axial region
Ankylosing spondylitis of cervical region
Ankylosing spondylitis of cervicothoracic region
Ankylosing spondylitis of thoracic region
Ankylosing spondylitis of thoracolumbar region
Ankylosing spondylitis lumbar region
Ankylosing spondylitis of lumbosacral region
Ankylosing spondylitis sacral and sacrococcygeal region
Juvenile ankylosing spondylitis

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Commonly asked questions

They will conduct blood tests to check for the HLA-B27 gene, which makes people more at risk of having ankylosing spondylitis. They will also conduct imaging tests to confirm it and see its location.

If ankylosing spondylitis is left unchecked and untreated for too long, patients will be at risk of getting spinal fractures, their spines curving forward, osteoporosis, chest pain, impacted breathing, nerve scarring, and heart disease.

Conservative treatment involves getting regular exercise to slow down or stop the disease from progressing. It also involves taking nonsteroidal anti-inflammatory drugs and disease-modifying anti-rheumatic drugs. Some might administer corticosteroid injections.

If the disease has progressed and the spine has been severely impacted, surgery might be needed to implant artificial joints and correct any curves.

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