Health care coverage in the United States includes a broad set of medical services, from routine checkups to major surgeries. If you have a plan through the marketplace, an employer, Medicaid, or Medicare, your coverage will vary in the details, but federal law sets a baseline. All marketplace and small group plans must cover ten categories of essential health benefits, and most plans share common rules about what’s included, what’s free, and what you’ll still pay for out of pocket.
The 10 Essential Health Benefits
Under the Affordable Care Act, individual and small group insurance plans must cover at least ten categories of services:
- Outpatient care: doctor visits, specialist appointments, and same-day procedures that don’t require a hospital admission.
- Emergency services: emergency room visits, including at out-of-network hospitals.
- Hospitalization: overnight stays, surgeries, and other care when you’re formally admitted.
- Maternity and newborn care: prenatal visits, labor and delivery, and care for your baby.
- Mental health and substance use services: therapy, counseling, inpatient treatment, and behavioral health care.
- Prescription drugs: at least one drug in every category and class on the plan’s approved list.
- Rehabilitative and habilitative services: physical therapy, occupational therapy, speech therapy, and devices that help you recover or gain function.
- Lab services: blood tests, imaging, and diagnostic work.
- Preventive and wellness services: screenings, immunizations, and chronic disease management.
- Pediatric services: children’s dental and vision care, plus all of the above for kids.
Large employer plans aren’t technically required to follow the same essential health benefits rules, but most cover the same categories because they’re competing for employees and following industry standards. If you’re unsure, your plan’s Summary of Benefits and Coverage document spells out exactly what’s included.
Preventive Care at No Extra Cost
Most plans must cover a set of preventive services with no copay, no coinsurance, and no deductible, as long as you see an in-network provider. This includes immunizations, screening tests, and wellness visits. The specific list differs by group: all adults, women specifically, and children each have their own set of covered preventive services.
For adults, this typically means blood pressure screening, cholesterol checks, diabetes screening, certain cancer screenings, and recommended vaccines. Women’s preventive services include well-woman visits, breast and cervical cancer screenings, birth control and related counseling, breastfeeding supplies and support, and STI screenings. Children are covered for developmental screenings, immunizations, and vision and hearing checks. The key detail: these services are only $0 when you use an in-network provider. Go out of network and you may owe the full cost.
Mental Health and Addiction Treatment
Federal parity law requires health plans to cover mental health and substance use treatment on equal terms with medical and surgical care. Your plan cannot charge higher copays for therapy than it charges for a comparable medical visit, impose stricter visit limits on mental health treatment, or require extra hoops like prior authorization for psychiatric care if it doesn’t require the same for similar medical services. The rule applies to financial requirements (copays, deductibles, coinsurance) and to less obvious restrictions like how plans decide which providers are in-network or how they handle claims.
In practice, this means that if your plan covers 30 days of inpatient care for a medical condition, it cannot cap inpatient addiction treatment at 15 days. Plans also cannot design their systems in ways that create a greater burden on people seeking mental health care compared to those seeking medical care, even if the restriction isn’t a hard number.
Prescription Drug Coverage and Tiers
Your plan maintains a formulary, which is its approved list of covered medications. Drugs are organized into tiers, and the tier determines what you pay. A common structure looks like this:
- Tier 1 (lowest cost): generic drugs, often with a small copay.
- Tier 2 (moderate cost): preferred brand-name drugs the plan has negotiated a better price on.
- Tier 3 (higher cost): non-preferred brand-name drugs.
- Specialty tier (highest cost): very expensive medications, often for complex conditions like cancer or autoimmune diseases.
If your doctor prescribes something that isn’t on your plan’s formulary, you can ask for an exception or switch to a covered alternative. Plans update their formularies periodically, so a drug that was covered last year might move to a higher tier or drop off entirely. Always check your plan’s current drug list before assuming your medication is covered at the same price.
Emergency and Hospital Care
Your insurance company cannot charge you more for going to an out-of-network emergency room. You don’t need prior authorization for emergency services, and your copay and coinsurance must be the same as they would be at an in-network facility. In a true emergency, go to the nearest hospital. The financial protections kick in automatically.
Once you’re at the hospital, whether you’re classified as an inpatient or outpatient matters for your bill. You’re considered an inpatient only when a doctor writes an order formally admitting you. If you go in for outpatient surgery and they keep you overnight for observation but never formally admit you, you’re still an outpatient. This distinction changes which part of your coverage pays, what your copay looks like, and whether follow-up care (like a stay in a skilled nursing facility) is covered. An inpatient admission is generally appropriate when you’re expected to need two or more midnights of medically necessary hospital care. If you’re unsure of your status during a hospital stay, ask. It directly affects your costs.
Maternity and Newborn Care
Marketplace plans must cover pregnancy and childbirth as an essential health benefit. This includes prenatal visits, labor and delivery, and postpartum care. Plans are also prohibited from charging women higher premiums than men of the same age, a practice that was common before the ACA.
Beyond the basics, women’s preventive services related to pregnancy are covered without cost-sharing. That includes breastfeeding supplies and lactation support, well-woman visits, and screening for conditions like gestational diabetes. Newborn care, including the hospital stay after birth, falls under pediatric services and is covered from day one.
Chronic Disease Management
If you have ongoing conditions like diabetes, asthma, or arthritis, your plan covers more than just occasional doctor visits. Chronic disease management is one of the ten essential health benefit categories, which means your plan should cover the ongoing care these conditions require: regular monitoring, necessary medical supplies, and education about managing your health.
For people with two or more serious chronic conditions expected to last at least a year, Medicare (and many private plans modeled after it) covers coordinated care management. This includes a comprehensive care plan listing your health problems, goals, medications, and providers. It also covers 24/7 access to a care team for urgent needs, medication reviews, and support when transitioning between care settings, like moving from a hospital stay to home recovery. Your provider will typically ask you to sign an agreement to receive these services on an ongoing monthly basis.
What Medicaid Covers
Medicaid is required by federal law to cover a core set of services in every state. These mandatory benefits include inpatient and outpatient hospital care, doctor visits, lab and X-ray services, nursing facility care, home health services, family planning, and transportation to medical appointments. Children on Medicaid receive especially broad coverage through the Early and Periodic Screening, Diagnostic, and Treatment program, which covers any medically necessary service a child needs, even if it isn’t on the state’s standard benefit list.
States can also add optional benefits on top of the mandatory ones. That’s why Medicaid coverage for things like dental care, vision, physical therapy, and prescription drugs varies by state. Medicaid is also required to cover medication-assisted treatment for opioid use disorder in every state.
What Health Insurance Typically Doesn’t Cover
Even comprehensive plans have exclusions. The most common are elective cosmetic surgery (procedures done purely for appearance rather than medical necessity), experimental or investigational treatments, long-term custodial care (help with daily activities like bathing and eating, as opposed to skilled medical care), and services not deemed medically necessary by the plan.
The “experimental treatment” exclusion is one of the most contested areas in health insurance. There’s no universal definition of what counts as experimental, and insurance contracts often don’t define the term precisely. This ambiguity can become a real problem when you need a newer treatment that your doctor recommends but your insurer considers unproven. If your plan denies a claim on this basis, you have the right to appeal.
Adult dental and vision care are also not included in most medical plans unless you buy a separate policy. Pediatric dental and vision are covered as essential health benefits, but once you turn 19, you typically need a standalone plan for those services.
Out-of-Pocket Limits
Every marketplace plan caps how much you pay out of pocket in a given year. For 2025, the maximum is $9,200 for an individual and $18,400 for a family. In 2026, those limits rise to $10,600 for an individual and $21,200 for a family. Once you hit that ceiling, your plan pays 100% of covered services for the rest of the year.
These limits include your deductible, copays, and coinsurance for in-network care. They don’t include your monthly premium, and they don’t count spending on out-of-network care or services your plan doesn’t cover. If you’re choosing between plans, the out-of-pocket maximum is one of the most important numbers to compare, especially if you have a chronic condition or expect significant medical care during the year.