M40.3
Non-Billable

Flatback syndrome

Non-Billable / Non-Specific Code

What is Flatback syndrome?

ICD-10-CM M40.3 is the diagnosis code for Flatback syndrome. This code falls under the section "Deforming dorsopathies" within Chapter 13 — Diseases of the musculoskeletal system and connective tissue (M00-M99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.

Coding Guidelines for M40.3

Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.

ICD-10-CM Code Hierarchy

Understanding where M40.3 sits in the ICD-10-CM classification helps ensure proper coding:

Sub-Codes 4 entries
M40.30Flatback syndrome, site unspecifiedBillableM40.35Flatback syndrome, thoracolumbar regionBillableM40.36Flatback syndrome, lumbar regionBillableM40.37Flatback syndrome, lumbosacral regionBillable
Related Codes

Frequently Asked Questions

Is M40.3 a billable ICD-10-CM code?

No, M40.3 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.

What does M40.3 mean?

M40.3 is the ICD-10-CM diagnosis code for "Flatback syndrome". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What is the parent code of M40.3?

The parent code of M40.3 is M40 ("Kyphosis and lordosis"). M40.3 provides a more specific classification within this category.

What section is M40.3 in?

M40.3 is located in Section M40-M43 — "Deforming dorsopathies" within Chapter 13 of the ICD-10-CM Tabular List.

What are the sub-codes of M40.3?

M40.3 has 4 sub-code(s) that provide more specific detail: M40.30, M40.35, M40.36, M40.37.

When should I use M40.3?

Use M40.3 when the patients documented diagnosis matches "Flatback syndrome" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.

People Also Ask

What is the ICD-10 code for Flatback syndrome?

The ICD-10-CM code for Flatback syndrome is M40.3.

Can M40.3 be used for primary diagnosis?

No, M40.3 is non-billable. Use a more specific sub-code for primary diagnosis billing.

What chapter is M40.3 in?

M40.3 is in Chapter 13 of the ICD-10-CM Tabular List.

Is M40.3 valid for 2026?

Yes, M40.3 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousM40.299Other kyphosis, site unspecifiedNext →M40.30Flatback syndrome, site unspecified
Code Details
M40.3
Flatback syndrome
Non-Billable / Non-Specific Code
13 — Diseases of the musculoskeletal system and connective tissue (M00-M99)
M40-M43 — Deforming dorsopathies
2026 ICD-10-CM