Surgeries are traditionally associated with hospital settings, leading many to ask, What is an ambulatory surgical center (ASC)? ASCs have provided outpatient surgical care since the 1970s, offering patients a convenient, cost-effective alternative to hospital-based services. These facilities are heavily regulated to ensure high-quality care, safety, and optimal patient outcomes — often at a lower cost than inpatient services.
Understanding what’s offered within ambulatory surgical care (meaning, its associated patient services) can help you better navigate these settings, whether you’re considering investing in a practice or evaluating a specific ASC. No matter your role, knowing the difference among today’s diverse healthcare facilities is essential. Use this ASC overview — with answers to common questions — to fully explore how these types of surgery centers benefit surgical patients and the wider health systems landscape.
What Is Considered an Ambulatory Surgery Center? Definition
According to the American Hospital Association (AHA), the general definition of ambulatory surgery center is a healthcare facility that provides same-day surgical care, including diagnostic and preventive procedures.
However, state licensing requirements can also influence how ASCs are classified. For example, in Illinois, surgical procedures must account for more than 50% of a facility’s care activities for a facility to be classified as an ASC. In contrast, Washington State applies a broader definition in answer to the question, What is an ASC in healthcare? There, any facility where patients are discharged within 24 hours of receiving specialized surgical services qualifies as an ASC.
Federally, the Centers for Medicare and Medicaid Services (CMS) guidelines for ambulatory surgery centers dictate that the facility must be spatially distinct from any hospital or critical access hospital surgical center and that patients are admitted and discharged for surgical services within the same day (consistent with the appropriate Conditions of Participation).
What Is an Ambulatory Surgery Center vs. Outpatient Hospital?
Is an ambulatory surgery center a hospital because it provides highly invasive, specialized patient care? No. ASCs are freestanding facilities that are financially and administratively separate from any hospital networks.
The key differences between an ambulatory surgery center vs. outpatient hospital largely lie in their scope of surgical services and ability to manage complex postoperative needs. Hospital outpatient surgical departments can perform procedures that may require extended, postoperative monitoring or inpatient follow-up. The same is not true for ambulatory surgical care, meaning, an ASC typically only serves patients who can safely undergo surgery and discharge that same day.
For both these providers of same-day patient services, additional differences include:
- Facility ownership. ASCs typically are independently owned by physicians, optometrists, or dentists, while outpatient hospitals are part of a larger hospital system.
- Costs. ASCs are documented to have lower overhead costs than outpatient hospitals.
- Patient populations. ASCs generally serve healthier patient populations, while outpatient hospitals may treat patients with more complex conditions.
What Is an Ambulatory Surgical Center's Purpose?
In response to ongoing frustrations about limited operating room availability and scheduling delays, two physicians opened the country’s first ASC in 1970. Today, more than 6,000 Medicare-certified ASCs operate across the U.S., delivering care to millions of surgical patients.
Widened access is one of the primary purposes of ambulatory surgery. Examples of advantages that ASC patients enjoy alongside easier scheduling include:
- Shorter procedure times, by about 26% compared to hospital-based procedure lengths.
- Lower cost of care, because ASC-based surgeries have shown to be as much as 60% less expensive.
- Reduced rates of surgical site infections, by as much as half of those experienced by hospital-based surgical patients.
- Higher rates of patient satisfaction, potentially due to convenience, a less stressful overall experience, and a more standardized approach to perioperative care.
What Are Some Common Surgeries Performed at an ASC?
The surgeries conducted in ASCs are typically less invasive than those conducted in inpatient settings. Some common ambulatory surgery examples include:
- Bone fracture repairs
- Knee and hip replacements
- Eye surgeries (e.g. cataract removal)
- Oral surgeries (e.g., wisdom tooth removal)
- Plastic surgeries
- Hernia repairs
- Biopsies
Because of the nature of these procedures, patients can typically go home on the same day of their surgery. In rare cases, patients may be monitored for up to 72 hours. However, length of stay depends largely on state regulations, and not all ASCs offer overnight services.
What Additional Services Do ASCs Provide?
In addition to surgeries, ASCs also offer a range of diagnostic and preventative procedures, such as colonoscopies and endoscopies. ASCs also have multidisciplinary teams of surgeons, anesthesiologists, and nurses responsible for managing a patient's pain and recovery needs. In the limited cases where patients may stay overnight, they're typically offered meals.
How Are Ambulatory Surgical Centers Regulated?
At the federal level, all ambulatory surgical centers participating in Medicare and Medicaid programs must meet regulations outlined by CMS. There are also several accrediting bodies, such as The Joint Commission, that work to ensure that ASCs are meeting minimum safety and care standards.
At the local level, each state has its own laws governing the operation and licensing of an ASC. Healthcare leaders can get more information about their state's requirements through their local health department.
Are Ambulatory Surgery Centers Safe?
Some people may have concerns about undergoing surgeries in outpatient settings. However, ASCs are held to strict regulatory standards, making them a safe and reliable alternative to inpatient hospitals.
Studies have even shown that patients undergoing surgeries at ASCs have lower rates of 30-day revisits and complications compared to those undergoing hospital-based surgeries. This reflects the rigorous patient selection process used by physicians working in ASCs, ensuring that patients requiring a higher level of care are appropriately referred to hospitals.
Why Are ASCs Cheaper Than Hospitals?
ASCs offer a more cost-effective alternative to hospital-based surgeries since they function on a much smaller scale. These centers focus on efficiency and fast turnarounds, which reduces the overhead costs associated with extended stays. There are also less costs associated with equipment maintenance, since ASCs provide a very specific range of services.
Medicare typically reimburses ASCs at a lower rate than hospitals for the same procedures. On average, ASCs receive about 58% of the reimbursement rates that hospitals do, which reflects their lower operating costs.
Keep Up With the Changing Healthcare Landscape
Beyond asking, What Is an Ambulatory Surgery Center? you may be wondering what other types of services and facilities are reshaping the industry. Stay in the know and get the latest healthcare news and insights that can help you and your team thrive.