Therapy Session Caps and Annual Visit Limits: The MHPAEA Quantitative Parity Appeal

QTL vs. NQTL: why session caps are a different argument

Most MHPAEA appeals target non-quantitative treatment limitations — prior authorization requirements, medical necessity criteria, step-therapy protocols, network composition rules. These are the NQTLs that dominate the DOL's enforcement fact sheets and the CAA 2021 § 203 comparative-analysis demand — a general NQTL disclosure duty, and a different one from the QTL document-request right described below for session-cap appeals. If your practice is fighting a prior-auth denial, the prior authorization NQTL guide is the right starting point.

Session caps and annual visit limits are different. They are quantitative treatment limitations — limits expressed numerically and written directly into the plan's benefit design. Under 29 CFR § 2590.712(c)(1), a QTL may only be applied to mental health or substance use disorder benefits if, under the plan, it applies to “substantially all” (at least two-thirds by dollar value) of medical and surgical benefits in that classification, and then only at the most common (predominant) level used for medical/surgical benefits.

Practically: if a plan covers outpatient physical therapy, occupational therapy, cardiac rehab, and speech therapy with no annual visit caps — while capping outpatient psychotherapy at 30 sessions per year — the cap fails the “substantially all” test. It cannot be applied to behavioral health at all.

What CO-119 actually means — and what it doesn't

CARC code CO-119 is defined as: “Benefit maximum for this time period or occurrence has been reached.” In the behavioral health billing context it appears in two distinct scenarios, and the appeal strategy differs slightly for each.

If the denial is for the first or third scenario — a visit cap — the QTL parity argument applies directly. If it is the second scenario — a dollar cap on an ACA-qualified individual or small-group plan — that may also be an ACA violation independent of MHPAEA, because the ACA prohibits annual dollar limits on essential health benefits, and behavioral health is a mandatory essential health benefit category.

How the MHPAEA parity test works for visit caps

The 2013 MHPAEA implementing regulations establish a two-part test for quantitative treatment limitations in the “outpatient” classification (where most therapy claims land). Both parts must be satisfied before a visit cap can be applied to mental health benefits.

Step 1 — The “substantially all” test. Does the visit cap apply to at least two-thirds of the plan's medical and surgical outpatient benefits, measured by dollar value? The DOL's Self-Compliance Tool for MHPAEA (updated 2023) is the authoritative guide for running this calculation. Most commercial plans offer a wide range of outpatient medical/surgical services — specialist office visits, physical therapy, occupational therapy, cardiac rehabilitation, speech therapy, dialysis — without a per-visit or per-year cap. When you add up the claim dollars for all those uncapped services, they typically exceed two-thirds of all outpatient medical/surgical dollars. If that's true, the plan fails Step 1 and cannot impose any visit cap on outpatient behavioral health.

Step 2 — The “predominant” test. If the cap does apply to substantially all outpatient medical/surgical benefits, the mental health cap cannot be stricter than the most common (predominant) limit used for medical/surgical benefits. If the plan applies a 60-visit cap to physical therapy and a 30-visit cap to psychotherapy, the mental health cap fails Step 2.

The plan is legally required to apply the cap consistently with the parity rules. Under ERISA § 104(b)(4) and 29 CFR § 2560.503-1(h)(2)(iii), you can demand the documents the plan relied on in writing; 29 CFR § 2590.712(d) requires the plan to disclose the criteria and factors used to apply the limit.

Common session caps by plan type — and when they violate parity

The specific cap a patient faces depends on their plan. Below are the most common patterns seen across major commercial payers and plan types. For plans MHPAEA actually covers, none of these caps is automatically compliant — each requires the plan to have passed the substantially-all and predominant tests. Traditional Medicare and Medicare Advantage aren't covered by MHPAEA at all (different rules govern inpatient psychiatric limits); Medicaid coverage depends on the delivery model, noted in the table below.

The highest-risk scenario is the large self-funded employer plan that has a 20- or 30-visit cap inherited from a plan design that predates MHPAEA's 2010 effective date for large employers. Those legacy caps are worth scrutinizing closely — plan designs from that era generally weren't built around MHPAEA's classification tests — and because the plan is self-funded, DOL EBSA (not the state insurance department) has enforcement authority.

Writing the appeal letter for a session-cap denial

A CO-119 QTL appeal has a different structure than a medical necessity appeal. You are not arguing clinical need — the plan already accepted the service as covered. You are arguing that the benefit design itself is unlawful. Five components make a complete letter.

1. Header with claim specifics. Patient name, member ID, date(s) of service, CPT code (typically 90834, 90837, 90847, or 90853), claim number, and the CO-119 denial code. State that the denied services are covered behavioral health services under the plan.
2. The parity assertion. Open the body with a clear statement: “This appeal asserts that the annual visit limit that produced this denial constitutes a quantitative treatment limitation that violates the Mental Health Parity and Addiction Equity Act of 2008, 29 U.S.C. § 1185a, and the implementing regulations at 29 CFR § 2590.712(c), because it is more restrictive than the limits applied to comparable medical and surgical outpatient benefits under the same plan.”
3. The ERISA § 104(b)(4) document demand. Include a written request for the plan's quantitative treatment limitation classification analysis and the documents relied on, under ERISA § 104(b)(4), 29 CFR § 2560.503-1(h)(2)(iii), and 29 CFR § 2590.712(d). Specifically: “Please provide the written analysis the plan used to determine that this visit cap applies to substantially all outpatient medical and surgical benefits and that it is no more restrictive than the predominant limit applied to those benefits.”
4. The comparator argument. Identify specific covered medical/surgical outpatient services that are not subject to the same visit cap. Physical therapy is usually the strongest comparator because it is functionally similar (ongoing outpatient treatment for a chronic condition) and because most plans do not cap it on the same terms. State: “This plan covers outpatient physical therapy [cite the plan document or Explanation of Benefits showing PT coverage without a comparable annual cap]. Imposing a [N]-visit annual cap on outpatient psychotherapy while applying no comparable cap to outpatient physical therapy is a more restrictive quantitative treatment limitation under 29 CFR § 2590.712(c).”
5. Escalation notice. Close by stating that if the plan does not either (a) overturn the denial and waive the cap as applied, or (b) produce a written classification analysis demonstrating that the cap is applied to substantially all outpatient medical/surgical benefits at the same level, you will file a complaint with the relevant regulator — state Department of Insurance for fully-insured plans, or DOL EBSA for ERISA plans — and pursue external independent review.

State laws that go further than federal MHPAEA on visit limits

For patients with fully-insured plans (not self-funded ERISA plans), several states have enacted parity requirements that are stronger than federal MHPAEA and that directly address the session-cap problem. Check your patient's state appeal guide for the specific statute and regulatory contact.

• California (SB 855, Health & Safety Code § 1374.72 / Insurance Code § 10144.5). California eliminated visit caps on mental health and substance use disorder treatment for state-regulated / fully-insured plans (not self-funded ERISA) effective January 1, 2021. SB 855 requires coverage of all medically necessary mental health and substance use disorder treatment on the same terms as medical/surgical care, and bars limiting that coverage to short-term or acute treatment — which in practice forecloses a flat numeric visit cap untethered to medical necessity. If a California fully-insured plan issues a CO-119 session-cap denial, cite both federal MHPAEA and California Health & Safety Code § 1374.72. Plans sold through Covered California (the state's ACA marketplace) are subject to the same rule; the DMHC and CDI are the regulators that enforce it.
• Illinois (215 ILCS 5/370c.1). Illinois's mental health and substance use disorder parity statute prohibits treatment limitations and financial requirements on those benefits that are more restrictive than the predominant limitation applied to substantially all medical/surgical benefits — a direct QTL prohibition that applies to individual, small-group, and large-group fully-insured plans in the state.
• New York (NY Insurance Law § 3221(l)(5) and § 4303). New York's parity requirements — rooted in Timothy's Law (Chapter 748 of the Laws of 2006) and its later amendments — prohibit quantitative limits on mental health benefits more restrictive than those applied to physical health. The state's Department of Financial Services (DFS), which absorbed the former Insurance Department in 2011, enforces this.

In all three states, a CO-119 denial on a fully-insured plan is worth evaluating as both a potential federal MHPAEA violation and a potential state parity violation. Consider filing with the state insurance regulator; if the plan is also subject to ERISA, DOL EBSA is a parallel option.

Escalation: what to do when the first appeal fails

Some QTL disputes resolve at the first internal appeal level — once the plan sees the parity assertion and the ERISA § 104(b)(4) / 29 CFR § 2590.712(d) document demand in writing, plans sometimes lift the cap or issue a new EOB without the session limit applied. When that does not happen, the escalation paths differ from a clinical denial.

External independent review (IRO). Non-grandfathered plans must offer external review for adverse benefit determinations, but eligibility commonly turns on whether the denial involves a medical judgment call — a straightforward numeric visit-cap application may not qualify the same way a medical-necessity dispute would. Confirm eligibility with the plan or your state's external review program before relying on this route, and don't let your internal-appeal deadline lapse while you check. For a QTL visit-cap dispute, the regulatory complaint routes below are usually the more reliable escalation path.

State Department of Insurance complaint (fully-insured plans). A written complaint citing the specific visit cap, the CO-119 denial, and the plan's failure to disclose the QTL classification analysis under 29 CFR § 2590.712(d) and ERISA § 104(b)(4) gives the regulator a concrete compliance question to act on — check your state DOI's typical complaint-response timeline, since it varies by state. Find your state's DOI through the NAIC consumer locator.

DOL EBSA complaint (self-funded ERISA plans). File a complaint at askebsa.dol.gov. For QTL violations, include the name of the plan, the specific visit cap that was applied, and evidence (from the plan document or provider directory) that comparable outpatient medical/surgical benefits do not carry the same cap. EBSA pursues both individual plans and patterns of violations across plan sponsors.

The MHPAEA parity guide covers the full escalation framework including how to combine a QTL violation with a parallel NQTL comparative-analysis demand to create the strongest possible case at the DOI or EBSA stage.

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