ICD-10 Code M35.7: Hypermobility syndrome diagnosis code

Key takeaways

ICD-10 Code M35.7 is the billable diagnosis code for hypermobility syndrome, a connective tissue condition marked by excessive joint laxity.

M35.7 is valid for reimbursement submission with Medicare, Medicaid, and commercial payers when supported by appropriate clinical documentation.

The Excludes1 note under M35.7 covers ligamentous laxity, NOS (M24.2-), so those two codes never appear on the same claim.

Ehlers-Danlos syndromes (Q79.6-) sit under Excludes2. That means M35.7 and a Q79.6x code can be reported together when the record documents both conditions.

Hypermobility spectrum disorder still has no dedicated ICD-10-CM code, so M35.7 remains the working convention. Clinically confirmed hypermobile EDS uses Q79.62 instead.

Practice management software like Pabau helps practitioners record Beighton Score findings and the systemic involvement an M35.7 claim needs.

ICD-10 Code M35.7 is the billable ICD-10-CM diagnosis code for hypermobility syndrome, a connective tissue disorder marked by excessive joint laxity. It also carries hypermobility spectrum disorder, which has no code of its own, and suspected hEDS while the workup is open. Because one code covers that much ground, the record has to show which presentation it was assigned for.

This reference covers the M35.7 code hierarchy, billable status, excludes notes, and the EDS and HSD coding distinction. It also covers documentation requirements, related codes, and the ICD-10-CM update that still causes coding errors.

ICD-10 Code M35.7 at a glance

ICD-10 Code M35.7 is a billable diagnosis code in the ICD-10-CM tabular list. The table below provides the essential reference data practitioners and coders need at a glance.

What does M35.7 mean? Understanding hypermobility syndrome

Hypermobility syndrome (HMS) is a systemic connective tissue disorder marked by joint laxity beyond the normal range. Musculoskeletal pain, fatigue, and autonomic symptoms often come with it. It sits within the M35 category, “Other systemic involvement of connective tissue”, because it reflects a generalized tissue vulnerability rather than localized joint looseness.

Clinicians encounter HMS most often in rheumatology, physical therapy, and primary care settings. Patients typically present in their teens or twenties with recurrent joint pain, sprains, and soft-tissue injuries disproportionate to the reported mechanism.

The Beighton Score is the most widely recognized screening tool for generalized joint hypermobility. It assesses nine movements across the spine and peripheral joints. A score of 4 or more out of 9 is the conventional positive screen in adults.

Clinical judgment and systemic symptoms then decide whether HMS is the right diagnosis. Per the Ehlers-Danlos Society’s 2017 nosology, Beighton is a supporting criterion rather than a standalone diagnostic requirement.

Beighton scoring covers general laxity, so a single symptomatic joint still needs its own examination. The lateral pivot shift test grades rotatory knee instability, and the drop jump test measures how well a patient controls a landing.

Key clinical features that coders and clinicians should note when using M35.7:

• Generalized joint hypermobility affecting multiple sites
• Musculoskeletal pain not explained by injury alone
• Fatigue and soft-tissue fragility
• Absence of a more specific diagnosis (EDS subtype, Marfan syndrome, etc.) that would warrant a different code
• Symptoms may include proprioceptive difficulties and autonomic dysregulation in more complex presentations

ICD-10 Code M35.7: Code details and hierarchy

Understanding the ICD-10-CM hierarchy helps coders confirm they are at the correct level of specificity. M35.7 is a terminal code, so there are no sub-codes beneath it. Sibling codes in the M35 category cover other named conditions, with M35.9 used when the record does not specify one.

Always verify the active status of M35.7 against the current fiscal year’s code tables. The CDC/NCHS ICD-10-CM web tool publishes the official annual tabular list. It is the authoritative source for confirming that a code remains valid for the billing year in question.

Is M35.7 a billable code?

Yes. M35.7 is a billable, specific ICD-10-CM code valid for HIPAA-covered reimbursement transactions. It meets CMS’s requirement for a diagnosis code at the highest level of specificity available.

For claim submission, payers typically require the diagnosis to be documented in the medical record by a qualified clinician before the date of service. M35.7 is accepted by Medicare, Medicaid, and commercial insurers.

Coverage for the associated treatments, such as physical therapy or specialist referrals, varies by payer policy and medical necessity criteria. Claims management software that stores diagnosis codes against each encounter cuts submission errors and denial rates.

• Billable status: Yes – valid for HIPAA-covered transactions
• Medicare acceptance: Accepted as a valid diagnosis code; coverage for associated treatments follows LCD/NCD policies
• Medicaid acceptance: Generally accepted; state-level coverage rules apply
• Commercial insurers: Accepted; prior authorization requirements vary by plan
• CMS verification: Confirm each FY at the CMS ICD-10 codes page

Includes and excludes notes for ICD-10 Code M35.7

The tabular list entry for M35.7 carries one inclusion term and two excludes notes. Read all three before assigning the code. They decide whether M35.7 stands alone or sits alongside another code on the claim.

Includes notes

M35.7 includes familial ligamentous laxity. Documentation describing familial ligamentous laxity is coded to M35.7, and the laxity itself needs no additional code.

Excludes1 note: Ligamentous laxity, NOS (M24.2-)

An Excludes1 note means the two codes are mutually exclusive and cannot appear together on the same claim. M35.7 carries a single Excludes1 note:

• Ligamentous laxity, NOS (M24.2-) – use the site-specific M24.2- code when the record documents loose or lax ligaments with no systemic hypermobility syndrome diagnosis behind them.

The choice turns on how the provider has framed the finding. Unqualified ligamentous laxity at one or more joints is a ligament disorder, coded to M24.2-. M35.7 applies once the record supports generalized hypermobility as a systemic condition, with the multi-site or familial picture that goes with it.

Excludes2 note: Ehlers-Danlos syndromes (Q79.6-)

An Excludes2 note means the excluded condition is not part of the code you are assigning, but the patient may have both at once. M35.7 carries one Excludes2 note, for Ehlers-Danlos syndromes (Q79.6-). M35.7 and a Q79.6x code may therefore be reported together when the record documents both conditions.

This is the note most often coded from memory, because it used to read differently. Ehlers-Danlos syndromes sat under Excludes1 for M35.7 through FY2021, which did make the two mutually exclusive. CDC moved the note to Excludes2 effective October 1, 2021, when Q79.6 was expanded into Q79.60 through Q79.69.

Most encounters still need only one of the two codes. Use the most specific one the documentation supports. Report both only where the provider has recorded two distinct diagnoses rather than one condition described two ways.

M35.7 vs Ehlers-Danlos syndrome codes: What’s the difference?

EDS and HMS present with overlapping symptoms, and ICD-10-CM files them in different chapters. The Q79.6x codes fall under congenital malformations, while M35.7 sits within systemic connective tissue disorders.

An Excludes2 note links the two, so they are not mutually exclusive. Pick the most specific code the documentation supports, then add the second one only when a second diagnosis is recorded.

Q79.62 for hypermobile EDS entered the tabular list in FY2022. Where a clinician has formally confirmed hEDS using the 2017 International Classification criteria, Q79.62 is the more specific code. M35.7 stays in play as the working code while that workup is open, and for symptomatic hypermobility that never meets the hEDS threshold.

Coding hEDS and hypermobility spectrum disorder with M35.7

This is an evolving area of ICD-10-CM coding. The following reflects current practice guidance and should be verified against the AHA Coding Clinic before applying to audit-sensitive claims.

Hypermobile EDS (hEDS): Q79.62 is the correct code once a clinician has documented a formal hEDS diagnosis meeting the 2017 nosology criteria. Where the diagnosis is suspected but not yet confirmed, M35.7 remains appropriate as the working code.

The Excludes2 note permits co-reporting. A record documenting both hEDS and a separate hypermobility syndrome diagnosis can therefore carry both codes.

Hypermobility spectrum disorder (HSD): No dedicated ICD-10-CM code exists for HSD as of FY2026. HSD is a newer classification from the 2017 nosology. It captures patients with symptomatic hypermobility who do not meet the full criteria for hEDS.

Current coding convention assigns M35.7 for HSD, because it is the closest billable match. That convention comes from the coding community rather than CMS or NCHS. Document the clinical basis for the diagnosis clearly to support the assignment.

• Confirmed hEDS (2017 criteria met): Use Q79.62
• Suspected hEDS, workup incomplete: Use M35.7 as a working code
• HSD (does not meet hEDS criteria, but symptomatic): Use M35.7 by current convention
• Generalized joint hypermobility without systemic symptoms: Clinical judgment required; M35.7 may still apply if HMS is the documented diagnosis

Related ICD-10 codes to know alongside M35.7

Hypermobility syndrome patients often present with comorbidities that need additional diagnosis codes on the same claim. The table below covers the most commonly used companion codes.

Practices using occupational therapy software with built-in ICD-10 lookups can attach these codes during the encounter rather than after it.

Verify all companion codes against the AAPC ICD-10-CM lookup for the current fiscal year. Where the record describes inflammatory rather than mechanical back pain, check M45.8 before coding the pain to M54.5-.

Documentation requirements for M35.7

A claim billed with M35.7 needs more than a code on an encounter form. Payers and auditors look for clinical documentation that justifies the diagnosis. The following requirements reflect standard medical necessity expectations for a systemic connective tissue disorder diagnosis.

Required documentation elements

• Clinical findings: Documented joint laxity at multiple sites, ideally from a structured range of motion assessment
• Beighton Score: Record the score and the specific joints assessed. A score of 4+ supports the diagnosis in adults, but document the rationale whatever the score
• Symptom history: Onset, duration, and functional impact of musculoskeletal pain, fatigue, or related symptoms
• Exclusion of more specific diagnoses: Note the differentials considered, such as EDS subtypes, Marfan syndrome, or osteogenesis imperfecta, and why they were ruled out
• Specialist involvement: Document any referral to rheumatology or genetics. That strengthens the clinical basis for the code
• Treatment plan: Physical therapy referral, pain management approach, or rehabilitation goals tied to the M35.7 diagnosis

Digital intake forms can capture Beighton Score findings and systemic symptom history before the appointment starts. That leaves less for the clinician to reconstruct afterward, and it keeps the documentation in step with both billing and regulatory standards.

Practices billing for HMS rehabilitation should keep diagnosis documentation and treatment records in one system. Physical therapy EMR software lets clinicians attach ICD-10 codes directly to session notes. That makes the link between the code and the documentation auditable.

Recent ICD-10-CM updates affecting M35.7

M35.7 has not been revised, renumbered, or deleted in the FY2024, FY2025, or FY2026 update cycles. The code remains active and billable under the same description, hypermobility syndrome.

The change that still trips practices up is older than that. FY2022 expanded Q79.6 into Q79.60 through Q79.69, and it moved Ehlers-Danlos syndromes from Excludes1 to Excludes2 under M35.7. Any internal guidance written before October 2021 still treats M35.7 and Q79.6x as mutually exclusive, and that is no longer correct.

• M35.7 status (FY2026): Active and billable, description unchanged
• Current Excludes1: Ligamentous laxity, NOS (M24.2-) – never reported with M35.7
• Current Excludes2: Ehlers-Danlos syndromes (Q79.6-) – co-reporting permitted when both are documented
• Q79.62 added (FY2022): The preferred code for clinically confirmed hypermobile EDS
• HSD coding (FY2026): No dedicated code added, so M35.7 remains the convention
• Annual verification: Confirm at the CDC/NCHS tool each October before the new fiscal year begins

Compliance management tools that flag outdated diagnosis codes at the encounter level keep a practice current. Nobody has to audit every patient record by hand to find the stale ones.

How Pabau supports ICD-10 diagnostic coding workflows

Accurate M35.7 coding depends on clinical documentation that travels with the patient across encounters. Practice management software like Pabau keeps that history in one place. Its clinical records management lets practitioners attach ICD-10-CM codes to patient records and individual encounter notes.

The diagnosis is stored at the record level. Every later visit surfaces the existing code for review or update, so nobody codes the same patient from scratch.

HMS patients form a significant caseload in many physical therapy practices. Pabau helps those teams track ongoing diagnoses and tie rehabilitation goals to the M35.7 record. The result is a documentation trail that stands up to a payer audit.

In a multi-clinician musculoskeletal practice, code assignment tends to drift between providers. Shared templates and a single patient record keep that assignment steady. Every clinician then applies M35.7 against the same documentation standard.

Streamline your diagnostic coding workflows

Pabau helps clinicians attach ICD-10 codes to clinical records, track diagnoses across encounters, and generate documentation that supports accurate claims. See how it works for connective tissue and musculoskeletal practices.

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Conclusion

The safe way to use M35.7 is to let the record decide. Where the documentation describes generalized hypermobility as a systemic condition, the code holds. Where it describes one lax joint and nothing more, M24.2- is the better answer.

If your coding guidance has not been reviewed since October 2021, that is the fix worth making this week. Anyone working from the old Excludes1 rule quietly drops legitimate Q79.6x diagnoses off claims, and the loss never shows up as a denial.

Pabau attaches ICD-10 codes to encounter notes and captures Beighton Score findings on configurable digital forms. Book a demo to see how that documentation chain supports an M35.7 claim from the first visit onward.

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Frequently asked questions