Part A (Inpatient hospital): The Complete Guide to Colorado

Medicare Part A is the foundation of your health insurance coverage once you reach age 65 or qualify through a recognized disability. Often simply referred to as “hospital insurance,” Part A is responsible for covering the physical facilities where you receive major care: inpatient hospitals, skilled nursing facilities, hospice environments, and limited home health services. If you are admitted to a hospital in Colorado—whether it is a sprawling medical center in Denver or a critical access hospital on the Western Slope—Part A is the mechanism that pays for your bed, your meals, and your general nursing care.

However, assuming that Part A covers “everything that happens in a hospital” is one of the most common and financially dangerous mistakes someone approaching Medicare eligibility can make. Part A operates on a complex system of benefit periods rather than annual deductibles, it strictly differentiates between being “admitted” and being held under “observation,” and it interacts with your employer coverage and tax strategies in highly specific ways.

This comprehensive guide details exactly how Medicare Part A works, who qualifies for it, how much it actually costs, and how it interacts with the broader Medicare landscape in Colorado.

The Core Concept: What is Medicare Part A?

When the federal Medicare program was created in 1965, it was divided into two distinct halves, which collectively form what is known today as Original Medicare. Part B was designed to cover medical services, outpatient care, and doctors’ fees. Part A was designed to cover the institutional costs of inpatient care.

To understand Part A, it helps to think of it as covering the “room and board” of major medical events. When you require hospitalization, the facility incurs immense costs simply to house you, feed you, and provide the overarching infrastructure of nursing staff and medical equipment. Part A absorbs these institutional costs.

Because of this structure, Part A is rarely used in isolation. When you undergo surgery, Part A pays the hospital for the use of the operating room, your recovery bed, and the nurses on the floor. Simultaneously, Part B pays the surgeon who performs the procedure and the anesthesiologist who monitors your vitals. Both halves work in tandem to cover a single hospitalization event.

The Four Pillars of Part A Coverage

Under guidelines established by the Centers for Medicare & Medicaid Services (CMS), Part A coverage is broken down into four distinct categories of care. Understanding the boundaries of these four categories is essential to predicting what Medicare will—and will not—pay for.

1. Inpatient Hospital Care

Inpatient hospital care is the primary service covered by Part A. This applies when you receive an official order from a doctor stating that you must be admitted to a hospital for inpatient care.

When you are admitted as an inpatient, Part A covers:

• A semi-private room (unless a private room is deemed medically necessary).
• Hospital meals and dietary services.
• General nursing care provided by the hospital’s staff.
• Drugs, medications, and medical supplies administered during your inpatient stay.
• Operating room and recovery room services.
• Intensive care unit (ICU) services.
• Blood transfusions (after you pay for the first three pints of blood in a calendar year).

Part A inpatient coverage applies to acute care hospitals, critical access hospitals, inpatient rehabilitation facilities, and long-term care hospitals. It also applies to inpatient mental health care in a psychiatric hospital, though Medicare imposes a strict lifetime limit of 190 days for inpatient psychiatric hospital care.

2. Skilled Nursing Facility (SNF) Care

If you require daily, skilled medical care or rehabilitation following a hospital stay, Part A will cover a temporary stay in a Skilled Nursing Facility (SNF). However, the rules governing SNF coverage are among the most rigid in the entire Medicare program.

To qualify for Part A SNF coverage, you must meet all of the following conditions:

• You must have had a qualifying inpatient hospital stay of at least three consecutive days (not counting the day of discharge).
• You must be admitted to the SNF within 30 days of leaving the hospital.
• Your doctor must certify that you require daily skilled care (such as physical therapy or intravenous injections) that can only be provided in a specialized facility.
• The condition you are being treated for in the SNF must be related to the condition you were treated for during your qualifying hospital stay.

If these conditions are met, Part A will cover your SNF room, meals, skilled nursing care, physical therapy, occupational therapy, speech-language pathology services, and medical social services. Part A covers up to 100 days of SNF care per benefit period, but as detailed later in this guide, cost-sharing begins well before day 100.

3. Hospice Care

Hospice care is designed to provide comfort and palliative support for beneficiaries who are terminally ill. If your doctor and the hospice medical director certify that you have a life expectancy of six months or less (assuming the illness runs its normal course), you can elect to receive hospice benefits under Part A.

When you elect hospice care, you agree to forgo curative treatments for your terminal illness and instead focus on comfort and symptom management. Part A covers:

• Doctor and nursing services for symptom control.
• Pain relief medications.
• Medical equipment (like wheelchairs or hospital beds) and supplies (like bandages and catheters).
• Short-term inpatient respite care (to give your primary caregiver a break).
• Grief and loss counseling for you and your family.

Crucially, Part A hospice coverage can be provided in your home, in a nursing facility, or in a dedicated hospice center. However, Part A does not pay for room and board if you receive hospice care in a nursing home or inpatient facility where you already live.

4. Home Health Care

While Medicare generally expects care to be delivered in clinical settings, Part A will cover limited home health services if you are homebound and require part-time or intermittent skilled nursing care or therapy.

“Homebound” is a strict CMS definition meaning that leaving your home requires a considerable and taxing effort, and that you typically only leave for medical appointments or short, infrequent non-medical events (like attending religious services).

If you qualify, Part A covers part-time skilled nursing care, physical therapy, occupational therapy, speech-language pathology, and part-time home health aide services (only if you are also receiving skilled nursing or therapy). It does not cover 24-hour care at home, meals delivered to your house, or homemaker services (like cleaning or laundry).

What Medicare Part A Explicitly Does Not Cover

Knowing what falls outside of Part A’s jurisdiction is vital for your financial planning. Part A will not cover:

• Physician Services: As mentioned, your doctors, surgeons, specialists, and anesthesiologists are covered by Part B, even if they treat you while you are in a hospital bed.
• Custodial Care: This is the most widely misunderstood exclusion in Medicare. Custodial care consists of non-medical assistance with activities of daily living—bathing, dressing, eating, using the restroom. Part A does not cover long-term custodial care in a nursing home, assisted living facility, or at home.
• Observation Status Stays: If you are kept in the hospital for monitoring but not formally admitted as an inpatient, your stay is considered an outpatient event and is billed to Part B, not Part A.
• Private Duty Nursing: Part A covers the general nursing staff provided by the hospital, but it will not pay for a private-duty nurse hired specifically for your individual care.
• Personal Convenience Items: Items like hospital room televisions, telephones, or private rooms (unless medically necessary) are excluded.

Eligibility and Work History: How You Earn Part A

Unlike many forms of health insurance, the cost of carrying Medicare Part A is directly tied to your lifetime work history and tax contributions. Over the course of your career, the payroll taxes deducted from your paychecks fund the Medicare trust. Your eligibility for “premium-free” Part A is determined by how many quarters of coverage you have accumulated.

You earn a quarter of coverage (a “credit”) by earning a specific minimum amount of income in a given calendar quarter. You can earn up to four credits per year.

If you have 40 or more quarters: If you or your current (or qualifying former) spouse accumulated at least 40 quarters of work history paying Medicare taxes, your monthly premium for Part A will be exactly $0. The vast majority of Coloradans fall into this category and never pay a monthly bill for Part A coverage.

If you have 30 to 39 quarters: If you fell short of the 10-year mark but accumulated at least 30 quarters of work history, you can buy into Part A, but you will pay a prorated monthly premium (which adjusts annually).

If you have fewer than 30 quarters: If you worked fewer than 30 quarters in jobs that withheld Medicare taxes, you must pay the maximum monthly premium to carry Part A. This full premium is substantial, often exceeding $500 per month depending on the exact plan year.

It is important to remember that even if you have to pay a premium for Part A, your eligibility to enroll at age 65 remains intact, provided you meet citizenship and residency requirements.

The Most Critical Mechanism: The Benefit Period

To understand the costs associated with Part A, you must completely discard the way you are used to health insurance deductibles functioning.

Most health insurance—including Medicare Part B, Medicare Part D, and standard employer plans—operates on an annual calendar-year deductible. You pay a certain amount out of pocket between January 1 and December 31, and once you hit that threshold, the insurance steps in for the rest of the year.

Medicare Part A does not use an annual deductible. It uses a “Benefit Period” deductible.

A benefit period is a measurement of time that tracks your usage of inpatient hospital and skilled nursing facility services.

• A benefit period begins the day you are admitted as an inpatient to a hospital or SNF.
• A benefit period ends when you have gone 60 consecutive days without receiving any inpatient hospital care or skilled nursing facility care.

Every time a new benefit period begins, you are responsible for paying the Part A deductible all over again, regardless of what month it is or how many deductibles you have already paid that calendar year.

Benefit Period Scenarios in Action

To illustrate how this works, consider the following examples using the general mechanism of the benefit period structure.

Scenario 1: The Single Stay You are admitted to a hospital in Denver in March for a planned knee replacement and stay for three days. You pay the Part A deductible. You recover well, go home, and require no further hospital care for the rest of the year. You paid the deductible exactly once.

Scenario 2: The Extended Illness (Same Benefit Period) You are admitted to a hospital in June for severe pneumonia. You pay the Part A deductible upon admission. After ten days, you are discharged. Three weeks later (21 days), you suffer a relapse and are readmitted. Because you have not been out of the hospital for 60 consecutive days, you are still in the exact same benefit period. You do not have to pay the Part A deductible a second time for this readmission.

Scenario 3: The Unfortunate Year (Multiple Benefit Periods) You are admitted to the hospital in February for a cardiac event. You pay the Part A deductible. You are discharged and recover fully. In August—well over 60 days later—you fall and require inpatient surgery for a broken hip. Because more than 60 consecutive days passed since your last inpatient stay, your first benefit period ended. Your August admission triggers a brand new benefit period, and you must pay the full Part A deductible a second time.

If you were hospitalized multiple times throughout the year with more than 60 days between each stay, it is entirely possible to pay the Part A deductible three or even four times in a single calendar year.

Understanding Out-of-Pocket Costs: Deductibles and Coinsurance

While most beneficiaries do not pay a monthly premium for Part A, you are still responsible for cost-sharing when you actually consume healthcare services. Part A structures this cost-sharing heavily around the duration of your stay within a single benefit period.

Inpatient Hospital Costs

The longer you remain in the hospital during a single benefit period, the more of the financial burden shifts back to you through daily coinsurance fees.

• Days 1 through 60: For the first 60 days of an inpatient stay, your only responsibility is the upfront Part A deductible. Whether you are in the hospital for three days or fifty-nine days, your cost remains flat at the deductible amount. Medicare covers everything else entirely.
• Days 61 through 90: If your hospital stay extends past 60 days in a single benefit period, Medicare stops covering the full cost. For days 61 through 90, you must pay a significant daily coinsurance fee out of pocket for every single day you remain in the hospital.
• Days 91 and Beyond (Lifetime Reserve Days): If you exhaust your 90 days of coverage in a benefit period, you can draw upon your “Lifetime Reserve Days.” Every Medicare beneficiary is granted 60 lifetime reserve days. For each of these days you use, the daily coinsurance penalty sharply increases (typically double the rate of days 61-90). Once a lifetime reserve day is used, it is gone forever. If you exhaust all 90 standard days and all 60 lifetime reserve days, Medicare Part A stops paying entirely, and you are responsible for 100% of all hospital costs.

Skilled Nursing Facility (SNF) Costs

The cost structure for a Skilled Nursing Facility operates on a similar timeline, but the duration of coverage is much shorter.

• Days 1 through 20: If you meet the strict SNF qualifying criteria (including the prior 3-day inpatient hospital stay), Part A pays 100% of your SNF costs for the first 20 days of your stay. You owe nothing.
• Days 21 through 100: If you require skilled care beyond day 20, you will be charged a daily coinsurance fee for days 21 through 100.
• Days 101 and Beyond: Medicare Part A SNF coverage hard-stops at 100 days per benefit period. From day 101 onward, you are responsible for all costs.

The “Two-Midnight Rule” and Observation Status

One of the most complex nuances of Medicare Part A—and a frequent source of billing shock for patients—is the legal distinction between being “admitted” and being held under “observation.”

Simply being assigned a hospital bed, receiving treatment from nurses, eating hospital food, and staying overnight does not mean you have been admitted as an inpatient. A hospital can classify you as an “outpatient under observation status” while they determine if you are sick enough to require formal inpatient admission.

Medicare enforces what is known as the “Two-Midnight Rule.” Under this guideline, CMS instructs doctors to formally admit patients only if they expect the patient will require hospital care that crosses at least two midnights. If the doctor expects the condition to be resolved faster than that, the patient should be placed in observation.

This classification matters tremendously for your billing:

1. Observation is Part B, not Part A: If you are under observation status, your entire stay is billed as outpatient care under Medicare Part B. You will pay standard Part B coinsurance (typically 20%) for every individual service, test, and drug you receive.
2. The SNF Trap: To qualify for Part A coverage in a Skilled Nursing Facility, you must have a prior inpatient hospital stay of at least three days. Time spent in observation status does not count toward this three-day requirement. You could spend four days in a hospital bed under observation, be transferred to an SNF for rehab, and discover that Medicare will pay absolutely nothing for the SNF because you were never formally admitted.

If you are hospitalized in Colorado, you or your family members should explicitly ask the hospital staff: “Am I formally admitted as an inpatient, or am I under observation status?”

Working Past 65: The HSA Trap

Many Coloradans continue to work past their 65th birthday, remaining on their employer’s group health insurance plan. Often, people in this situation elect to enroll in premium-free Part A anyway, reasoning that it costs nothing and can serve as secondary coverage if they require hospitalization.

While this strategy is generally sound, it triggers a massive complication if you have a High Deductible Health Plan (HDHP) and actively contribute to a Health Savings Account (HSA).

Under IRS regulations, you cannot contribute tax-advantaged money to an HSA if you are enrolled in any part of Medicare, including premium-free Part A. As soon as your Part A coverage becomes active, your legal ability to fund your HSA stops immediately. If you or your employer continue to deposit money into the HSA while you have Part A, you will face IRS tax penalties on those excess contributions.

Furthermore, if you delay Medicare enrollment until you retire at age 67, and you apply for Part A at that time, Medicare will retroactively backdate your Part A coverage by up to six months (but no earlier than your 65th birthday). Because of this retroactive six-month lookback, you must stop all contributions to your HSA a full six months before you actually apply for Medicare, or you will face tax penalties for the overlap.

How Part A Works with the Broader Medicare Landscape in Colorado

Original Medicare (Part A and Part B) is entirely administered by the federal government. You can use it at any hospital or facility in the United States that accepts Medicare. However, Original Medicare has no out-of-pocket maximum. If you face a catastrophic hospitalization that drains your lifetime reserve days, your financial exposure is mathematically limitless.

Because of this risk, virtually all Medicare beneficiaries in Colorado acquire supplemental coverage or opt for private Medicare administration. How Part A functions depends on the path you choose.

The Medicare Advantage Route (Part C)

Medicare Advantage plans are offered by private insurance carriers. If you enroll in a Medicare Advantage plan in Colorado, you are electing to have your Part A and Part B benefits administered by the private carrier rather than the federal government.

Currently, there are 103 real Medicare Advantage plans available across the state of Colorado, offered by carriers such as Aetna Medicare, Anthem Blue Cross and Blue Shield, Clear Spring Health, Devoted Health, Elevate Medicare Advantage, HealthSpring, Humana, Kaiser Permanente, Perennial Advantage, Select Health, and UnitedHealthcare. (For example, options range from HMO plans like AARP Medicare Advantage Essentials from UHC CO-2 to PPO options like AARP Medicare Advantage from UHC CO-0013).

By federal law, every Medicare Advantage plan must provide coverage that is at least equivalent to the Part A benefits offered by Original Medicare. They must cover your inpatient stays, your SNF care, your hospice, and your home health care.

However, Medicare Advantage plans change the cost structure entirely. Instead of dealing with the complex 60-day benefit period deductible of Original Medicare, a Medicare Advantage plan will impose its own cost-sharing rules. Often, an MA plan will charge a flat daily copay for the first five to seven days of a hospital stay (e.g., $300 per day for days 1-5), and charge nothing for the remainder of the stay. Additionally, MA plans cap your maximum out-of-pocket spending for the year, providing a safety net that Original Medicare lacks.

The tradeoff is network restrictions. If you have an HMO Medicare Advantage plan, you generally must use hospitals within that carrier’s specific Colorado network (except in emergencies).

The Medicare Supplement Route (Medigap)

If you remain on Original Medicare, you can purchase a Medicare Supplement (Medigap) policy to cover the out-of-pocket costs that Part A leaves behind.

Medigap plans are designed to pay the massive deductibles and coinsurances of Part A. For instance, the most popular Medigap plans (Plan G and Plan N) will pay the Part A benefit period deductible completely. If you go to the hospital, your Medigap plan pays the upfront cost. If you are readmitted in a new benefit period later that year, the Medigap plan pays the deductible again. Medigap plans also cover the Part A coinsurance for days 61-90 and provide coverage for an additional 365 lifetime reserve days after Medicare’s benefits are exhausted.

Because Medigap plans supplement Original Medicare, they do not utilize provider networks. You can use a Medigap plan at any hospital in Colorado—or anywhere in the country—that accepts standard Medicare.

When and How to Enroll in Part A

If you are already receiving Social Security retirement benefits or Railroad Retirement Board benefits when you turn 65, your enrollment in Medicare Part A is automatic. You will receive your red, white, and blue Medicare card in the mail roughly three months before your 65th birthday, and your Part A coverage will begin on the first day of your birthday month.

If you are not receiving Social Security benefits yet (which is common, as full retirement age is now 67 or older), you must proactively enroll in Part A.

The Initial Enrollment Period (IEP): This is a seven-month window that begins three months before your 65th birthday month, includes your birthday month, and ends three months after your birthday month. Enrolling during the first three months ensures your Part A coverage starts on the first of your birthday month.

The Special Enrollment Period (SEP): If you or your spouse are actively working and you have creditable group health coverage through that employer (with an employer size of 20 or more employees), you can delay Medicare Part A and B without penalty. Once that employment or coverage ends, you are granted an 8-month Special Enrollment Period to sign up for Medicare.

The General Enrollment Period (GEP): If you missed your IEP and do not qualify for a SEP, you must wait for the General Enrollment Period, which runs from January 1 through March 31 of each year, with coverage starting the month after you enroll. If you do not qualify for premium-free Part A, delaying enrollment could subject you to permanent late enrollment penalties, increasing your monthly premium by 10% for twice the number of years you could have had Part A but didn’t.

Making Your Decision: Next Steps in Colorado

Understanding Medicare Part A is the first critical step in building a secure retirement healthcare strategy. By mastering how benefit periods work, recognizing the limitations of skilled nursing facility coverage, and understanding the vital difference between inpatient admission and observation status, you can protect yourself from unexpected catastrophic hospital bills.

Your next steps should be:

1. Verify your work history: Confirm with the Social Security Administration that you have accumulated the 40 quarters necessary for premium-free Part A.
2. Evaluate your HSA: If you are working past 65 and contributing to an HSA, carefully calculate your timeline for stopping contributions six months before you intend to activate Part A.
3. Choose your delivery system: Decide whether you prefer to leave your Part A benefits under the federal umbrella of Original Medicare (protecting yourself with a Medigap policy) or shift the administration of your Part A benefits to a private Medicare Advantage plan operating in Colorado.

Frequently Asked Questions