What Is an HDHP? High Deductible Health Plan Explained

High Deductible Health Plans are everywhere in the American employer benefits market. They attract enrollees with lower monthly premiums and the opportunity to pair with a Health Savings Account — but they also generate enormous confusion about what's covered, what's not, and why bills keep arriving. Understanding how an HDHP actually works is essential before enrolling in one.

What Is an HDHP?

A High Deductible Health Plan is a type of health insurance plan characterized by a higher annual deductible and lower monthly premiums than traditional plans. The IRS sets the thresholds that define an HDHP for the purpose of HSA eligibility.

For 2025, IRS requirements for HDHP status:

• Minimum deductible: $1,650 for self-only coverage; $3,300 for family coverage
• Maximum out-of-pocket: $8,300 for self-only; $16,600 for family

These figures are adjusted annually for inflation. The key feature: you generally pay all covered healthcare costs out of pocket until you hit the deductible. Only then does the plan begin sharing costs through coinsurance.

How HDHPs Work

Under a traditional low-deductible plan, you might pay a $30 copay for a doctor visit and the insurance pays the rest. Under an HDHP, that same visit might cost you $150 because you haven't yet met your deductible. The insurance company isn't denying your claim — it's paying its portion, which happens to be zero until you reach the deductible threshold.

This is the single most common point of confusion for HDHP enrollees: receiving a large bill and assuming the claim was denied. In most cases, the claim was processed correctly. The insurer applied the negotiated rate (you still get the in-network discount), and your portion was 100% of that discounted rate because your deductible isn't met.

Once you meet your deductible, the plan shifts to coinsurance — typically 80/20 or 70/30 — until you hit the out-of-pocket maximum. After that, the plan covers 100% of covered services for the rest of the year.

The Preventive Care Exception

This is critically important: HDHPs must cover preventive care at no cost to you, even before your deductible is met. Under the ACA, preventive services include:

• Annual wellness visits
• Recommended vaccinations
• Cancer screenings (mammograms, colonoscopies, cervical cancer screening)
• Cholesterol and blood pressure screening
• Certain preventive medications (statin therapy for high-risk patients, for example)

If you were billed for a preventive service and your HDHP didn't cover it, that may be a wrongful denial worth appealing. Common pitfalls: a "preventive" visit that included diagnosis or treatment of a new condition gets reclassified as a diagnostic visit and loses the preventive billing status.

HSA Pairing: The Tax Advantage

One of the most powerful features of an HDHP is eligibility to open a Health Savings Account (HSA). For 2025:

• Individual contribution limit: $4,300
• Family contribution limit: $8,550
• Catch-up contribution (age 55+): Additional $1,000

HSA contributions are tax-deductible, grow tax-free, and can be withdrawn tax-free for qualified medical expenses. Unlike Flexible Spending Accounts, HSA funds roll over year after year and can be invested like a retirement account. Many financial planners consider the HSA the best tax-advantaged account available to working Americans.

To maintain HSA eligibility, you must be enrolled in a qualifying HDHP and not have any other non-HDHP health coverage (including Medicare, except in specific circumstances).

Common HDHP Denial Reasons (and Misunderstandings)

1. Deductible not yet met — not a denial. As noted above, most "denials" early in the year are simply your deductible being applied. Read your EOB carefully: if the plan processed the claim and assigned your cost-sharing, it wasn't denied.

2. Actual denials: medical necessity. HDHPs still review claims for medical necessity. Diagnostic imaging, surgery, specialty care, and mental health treatment can all be denied if the insurer decides the service wasn't necessary.

3. Preventive care billed incorrectly. If your annual physical included an incidental mention of an existing condition and the provider coded it as diagnostic rather than preventive, the claim may lose its zero-cost-sharing status. Appeal by requesting the billing be corrected to reflect the preventive nature of the visit.

4. Out-of-network care. HDHPs exist across plan types (some are PPOs, some are EPOs). If your HDHP has network restrictions, out-of-network care can be denied or result in much higher cost-sharing.

5. HSA expense disputes. If you use HSA funds for a non-qualified expense, the IRS — not your insurer — penalizes you. This is a tax issue, not an insurance denial, but it's worth understanding.

When the Deductible Feels Impossible

For patients managing chronic conditions or facing a sudden illness, the HDHP deductible can create serious financial strain. If you're in this situation:

• Maximize your HSA contributions early in the year so the funds are available when you need them.
• Ask your providers about payment plans — many hospitals and physician groups will work with uninsured or high-deductible patients.
• Check whether your HDHP includes any embedded deductibles for family coverage (some plans have both individual and family deductibles that apply simultaneously).
• Review whether you're actually on the right plan type for your health needs. At open enrollment, an HDHP makes most financial sense for generally healthy individuals.

What to Do If Your HDHP Actually Denies a Claim

If your EOB shows the claim was denied (not just applied to your deductible), follow the standard appeal process:

• File an internal appeal within 180 days citing the specific denial reason.
• Include clinical records and a physician letter of medical necessity.
• If denied again, escalate to External Independent Review: Complete Guide" class="auto-link">external review.
• For preventive care denials, specifically cite ACA Section 2713 and the applicable USPSTF recommendation grade for the service.

Fight Back With ClaimBack

ClaimBack's free AI tool drafts a professional appeal letter in minutes, tailored to your insurer and denial reason. Don't let a denial be the final word.

Fight your denial at ClaimBack →

Related Reading:

• How to Write an Insurance Appeal Letter
• What Is Medical Necessity?
• Internal vs External Insurance Appeal