Healthcare is becoming more accessible with over 6,300 Medicare-certified ambulatory surgery centers (ASCs) around the USA. In 2023, the market size for US-based ASCs was valued at 36.51 billion, and it is projected to reach 57.32 billion by 2031.
With such tremendous growth on the horizon, it is imperative that you understand the implications of accurate ASC coding on your facility’s revenue growth and longevity.
To help you in this matter, we have created a comprehensive guide on ambulatory surgery center coding, which includes the medical coding systems used for ASC services, the frequently reported ASC CPT codes, and coding best practices.
So, let’s get right to it!
What are Ambulatory Surgery Centers (ASCs)?
Ambulatory surgery centers (ASCs) are specialized healthcare facilities offering outpatient surgical care. Patients who need minimally invasive surgeries and short recovery time can skip the hassles of a hospital stay (overnight stay) and get same-day diagnostic, preventive, and treatment procedures.
ASC’s quick in-and-out model has transformed the lives of millions of Americans who want to save time and money associated with hospital-based procedures. All the ambulatory surgicenters operating in the USA are Medicare-certified and hold state licenses to ensure the highest level of compliant and quality healthcare. From surgeons to anesthesiologists and nurses to interventional radiologists, ASCs employ specialized staff for various medical specialties.
Medical Coding Systems for ASC Coding
Healthcare providers and insurance payers communicate in an encrypted language known as medical code sets. Every service that healthcare professionals provide to an insured patient is coded into digits (alphanumeric codes), which are processed by the insurance payers for accurate reimbursement.
The same rule applies to ambulatory surgicenters. Medical billers rely on the following coding systems for precise ambulatory surgery center (ASC) coding.
Current Procedural Terminology (CPT) Codes
CPT codes are issued and managed by the American Medical Association (AMA). There are more than 11,000 of these procedural codes to ensure that every medical service, including surgeries, is covered through these 5-digit code sets.
Although this standardized coding system effectively captures the details and dynamics of healthcare services, its annual revisions can be a nuisance, adding to the complexity of medical coding and billing.
Nonetheless, medical billing staff at the ASCs diligently use CPT codes for clean claim creation and rightful payment collection.
International Classification of Diseases (ICD) Codes
The International Classification of Diseases, tenth revision, clinical modification (ICD-10-CM) codes are globally recognized and used for diagnoses. In the USA, two healthcare committees maintain and update ICD-10 codes.
The Centers for Disease Control and Prevention (CDC) has set up a National Center for Health Statistics (NCHS), which maintains and revises ICD-10-CM codes, while the Centers for Medicare and Medicaid Services (CMS) manages ICD-10-PCS code sets.
The system helps healthcare providers convey a patient’s condition and support the medical necessity of the treatment procedures that follow. ASC practitioners also use the ICD-10-CM codes to report diagnoses.
HCPCS Level II Codes
Another standardized system that is utilized during ambulatory surgery center coding is the Healthcare Common Procedure Coding System (HCPCS) Level II code sets.
These can be identified by their single alphabet followed by 4 numeric digits and primarily cover non-clinical services such as products, supplies, and equipment used during medical procedures.
The HCPCS Level II codes are managed by the CMS and are revised quarterly.
Top 10 ASC CPT Codes for 2024
According to the Ambulatory Surgery Center Association (ASCA), the medical specialties that are most served in the ASCs include orthopedics, pain management, ophthalmology, gastroenterology, and plastic surgery.
Besides these, podiatry, otolaryngology, obstetrics/gynecology, and dental care are also routinely provided at ambulatory surgical centers. Hence, this year’s most used ASC CPT codes cover the procedures performed for these specialties.
CPT Code 66984 – Excision of Cataract with Removal of Lens
According to the data gathered from SurgeryCenterView, ASC CPT code 66984 was the most reported CPT code in the nation’s ambulatory surgery centers in 2023. Out of all the charges that were collected at ASCs in the previous year, code 66984 made up 8.5% of the share. It is used when an ophthalmologist performs a cataract surgery, and the average charge for this procedure is $3,867.
During this surgery, the opthalmologist uses aspiration or ultrasonic waves to remove an extracapsular cataract. After the excision, the provider inserts an artificial or intraocular lens prosthesis. The procedure is performed without endoscopic cyclophotocoagulation (a laser probe that shrinks the ciliary processes and treats glaucoma).
CPT Code 45385 – Colonoscopy with Removal of Lesion(s)
The second most performed procedure at ambulatory surgicenters around the country in 2023 was colonoscopy for the examination of the colon and rectum. Of all the charges collected in the year, the payments for ASC CPT Code 45385 contributed 4.3%, where the average service fee for the procedure was $2,009.
The provider uses a colonoscope, a long, thin, flexible, tube-like instrument with a light and a camera attached to one end, to check for tumors, polyps, and lesions. He inserts and uses this assistive instrument to remove the lesions with a snare and wire loop. The wire is tightened around the base of the lesion until it cuts through it.
CPT Code 45380 – Colonoscopy with Biopsy, Single/Multiple
ASC CPT code 45380 is used to charge for colonoscopy and simultaneous biopsy to diagnose conditions with symptoms like diarrhea, rectal bleeding, constipation, or abdominal pain. In 2023, payments collected from this procedure made up 4.3% of the share of all the charges at the country’s ambulatory surgery centers. The average cost of this procedure is $2,073.
A gastroenterologist uses a flexible colonoscope to examine the rectum and colon. He uses this assistive instrument and its camera to perform a biopsy and excise one or more areas of the tissue. The specimens are then submitted to a laboratory for detailed diagnosis.
CPT Code 43239 – Esophagogastroduodenoscopy, Biopsy, Single/Multiple
The fourth most performed procedure at ambulatory centers in 2023 was esophagogastroduodenoscopy (EGD) with a biopsy. ASC CPT code 43239 is used to denote that. The average charge for this procedure is $1,806, and last year alone, this procedure contributed 3.9% of all the payments made to the ASCs.
This ASC CPT code is reported when the provider performs an upper gastrointestinal endoscopic examination or EGD to check for abnormalities in the stomach, esophagus, or duodenum. He inserts a flexible endoscope in the mouth and pushes it down the esophagus to remove one or more tissues for diagnostic tests.
CPT Code 45378 – Diagnostic Colonoscopy
Diagnostic colonoscopy for the rectum and colon was the fifth most performed medical procedure at ambulatory surgicenters. During ASC coding, it was noted that CPT code 45378 made up 2.3% of the total charges. The average service fee for diagnostic colonoscopy at ambulatory centers is $1,949.
This diagnostic test includes the insertion of a colonoscope (a long, flexible tube with a camera attached to one end) to check for abnormalities in the colon and rectum. The provider guides the colonoscope and takes a mucosa sample or tissue with a brush for diagnostic analysis. The colon-rectum area is then washed with warm saline, and the specimen is sent to a lab for diagnosis.
CPT Code 64483 – Injection(s), Anesthetic Agent and/or Steroid, Lumbar/Sacral
ASC CPT code 64483 reports the administration of an anesthetic agent in the lumbosacral region via an injection. It is the 6th most used CPT code at ambulatory surgicenters and contributes 1.3% to the total charges. The medium cost of this procedure is $2,473.
A provider uses a single-level transforaminal epidural injection to administer an anesthetic agent, steroid, or both in the lumbar or sacral area. It is a commonly performed procedure for pain management.
CPT Code 00812 – Anesthesia for Lower Intestine Scope, Colonoscopy
Another code that has been the highlight of ambulatory surgery center coding is 00812. In 2023, it made up 0.9% of the total charges at ASCs. The code reports an anesthetic procedure for colonoscopy in the lower intestine. The average charge for this procedure is $974.
An anesthesiologist administers anesthesia on a patient undergoing diagnostic colonoscopy. For accurate reimbursement, the ASC CPT code 00812 must match the surgical CPT code for inserting an endoscope into the lower intestine (duodenum).
CPT Code 64635 – Destruction of Lumbar/Sacral Facet Joint(s) by Neurolytic
The 8th most used ASC CPT code is 64635. It also contributed 0.9% to the total charge collection. Ambulatory surgicenter providers report this code when they use a neurolytic agent to destroy nerve tissue in the lumbosacral region. The median cost of this procedure is $3,973.
A provider uses CT scanning or fluoroscopic imaging to apply a neurolytic agent (e.g., thermal, chemical, electrical, or radiofrequency) on a single level of the paravertebral joint for nerve destruction.
CPT Code 69436 – Incision of Eardrum to Create Opening
ASC CPT code 69436 is used by ENTs to report a tympanostomy. The payments collected for this surgical procedure were 0.8% of all payments received at USA’s ambulatory centers in 2023.
Tympanostomy is a surgical procedure that requires the insertion of a ventilation tube in the eardrum to create an opening. The provider performs this procedure after administering general anesthesia, and it helps promote fluid drainage in the middle ear. The average cost of this surgery is high, nearly $3,366.
CPT Code 00142 – Anesthesia for Lens Surgery
The last code on our ‘Top 10 ASC CPT Codes’ list is 00142. Last year, it contributed 0.7% to the total charges at the ambulatory surgery centers. This ASC CPT code tells the insurance payer that an anesthetic service was performed for eye lens surgery. The average cost for such a procedure is $772.
When an anesthesiologist uses an anesthetic agent for pain relief during a cataract surgery, CPT code 00142 is used. It must be used alongside the surgical CPT code that indicates the removal of a damaged or clouded eye lens and replacing it with an intraocular prosthetic lens. The purpose of these procedures is to restore a patient’s vision.
Most Used ASC CPT Codes for E/M Visits
The ambulatory surgery centers provide complete pre-, intra, and post-operative surgical care in the shortest time. Therefore, evaluation and management (E/M) visits are essential ASC services.
Let’s look at the two most commonly used ASC CPT codes for E/M visits.
CPT Code 99213 – E/M Visit, Established Patient, 20 mins
During ambulatory surgery center coding, medical billers found that charges for an office or outpatient visit of an established patient, lasting up to 20 minutes, were created 0.1% of the time. They also revealed that the median charge for this E/M visit was $191.
Hence, ASC CPT code 99213 is used when an established patient meets a physician for 20 minutes in an ambulatory surgery center setting.
CPT Code 99214 – E/M Visit, Established Patient, 30 mins
This ASC CPT code is similar to the one above. The only exception is that it indicates 30 minutes of meeting time instead of 20. Moreover, in the previous year, it was reported 0.2% of the time, and the average charge for this E/M visit was $277.
Most Common ASC Cosmetic Surgeries & Their CPT Codes
The most frequently performed cosmetic surgeries at ambulatory surgicenters are abdominoplasty (a reconstructive surgery to tighten the muscles and skin in the abdomen), rhinoplasty (plastic surgery for altering and reconstructing the nose), and blepharoplasty (cosmetic surgery for removing excess skin and fat from the eyelids).
Hence, plastic surgeons report ASC CPT codes 30420 and 30462 for rhinoplasty, codes 15822 and 15823 for blepharoplasty, and code 15847 for tummy tuck or abdominoplasty the most.
Most Common ASC Gynecology Procedures and Their CPT Codes
Ambulatory gynecology is gaining popularity as more women seek quicker treatments and more accessible alternatives to a hospital’s outpatient visits and in-patient procedures. In the USA, some of the most performed gynecological procedures include cervical biopsies, tube litigation, and endometrial ablation (a minimally invasive surgery to remove the endometrial lining of the uterus).
Therefore, the most commonly reported ASC CPT codes for gynecology services are 58563, 57500, and 58600 for endometrial ablation, cervical biopsy, and tube litigation, respectively.
ASC Coding Guidelines
Recent stats indicate that the medical claim denial rate for ambulatory surgery centers is less than 5%. However, this may vary from facility to facility and for each medical specialty served at the ASC.
For example, a multi-specialty, Medicare-certified ASC offering plastic surgeries may have a denial rate of up to 28%. According to Becker’s ASC Review, the denial rate for plastic surgeries is the highest and stands at 28%.
So, as a whole, claim denials are inevitable, especially when you have a high patient inflow and file dozens of medical claims each day. However, you can reduce the rate if you follow coding best practices.
Consider the following ASC coding guidelines to improve the chances of clean claims filing and getting your reimbursements on time.
Code to the Highest Level of Accuracy
Precision and accuracy are the key elements of ASC coding. Always use the correct CPT codes for performed procedures, ICD-10-CM codes for diagnosing diseases and conditions, and HCPCS Level II codes for reporting the drugs, supplies, or equipment used during diagnostic or treatment procedures.
Besides using the correct codes, you must also know their proper placement in the medical claims. For example, when adding a Qualifying Circumstances CPT code for anesthesia (e.g., 99100), report the add-on code after the primary anesthesia CPT code for billing accuracy.
Similarly, always add the modifiers after the 5-digit CPT codes with a hyphen in between. For example, 99213-59 for an outpatient office visit with an established patient, lasting 20 to 29 minutes, where modifier 59 indicates that the E/M visit is separate and distinct from other services provided the same day.
Provide Complete Documentation
Supported your claims with adequate documentation to prevent denials. Along with the claim form, you must submit clinical notes, test reports, patient’s complete medical records, prescriptions, and discharge forms to help the insurance payer understand the medical necessity of a procedure or service.
Keep Up with Revisions in Code Sets
Another important ASC coding tip is to be aware of the updates (additions or deletions) to the coding systems. We have discussed above that CPT codes are revised annually, whereas ICD-10-CM codes may be revised twice a year, and HCPCS codes are updated quarterly. So, you must stay abreast of these revisions to report the correct codes in your medical claims.
Follow Payers’ Requirements
Every insurance payer, be it Medicare/Medicaid or a commercial insurer, has its own policies and requirements for claim submissions. For example, payers’ filing deadlines vary across the board, and late filings result in claim denials. Some payers only give you 90 days to file a claim, while others may stretch this timeframe up to a year. So, you must read each payer’s contract thoroughly and follow their requirements to mitigate denials.
Use Modifiers Judiciously
Modifiers are 2-digit codes (numeric, alphanumeric, or alphabetic) that offer more details about a procedure or service. They can be used with ASC CPT codes or HCPCS Level II codes to help the insurance payer understand the complete situation.
You must remember that one of the top 5 reasons for claim denials is ‘missing or incorrect modifiers’. Hence, their appropriate use can save you from losing revenue.
The most used modifiers in ambulatory surgery center coding are:
- Modifier 51 – Indicates that the provider performed multiple procedures in the same session.
- Modifier 52 – Indicates reduced or eliminated services at the physician’s discretion.
- Modifier 73 – Indicates that the ASC service was discontinued before administering anesthesia.
- Modifier 74 -Indicates that the ASC service was discontinued after administering anesthesia.
- Modifier KX – Indicates that the service provided was medically necessary even though it exceeds Medicare’s allowable amount.
Outsource ASC Coding to Professionals
If you are unable to handle the intricacies of ASC coding and are tired of receiving denial letters due to coding errors, then it is time to invest in reliable medical coding services. These services are offered by certified professional coders who are experts at their craft and can promise quick turnarounds.
Final Word
As part of the nation’s ambulatory surgery center network, your facility’s sustainability and success depend on accurate ASC coding. By using the correct ASC CPT codes and implementing the ASC coding guidelines, you can improve your chances of submitting first-pass claims for revenue optimization.
However, if the ambulatory surgery center coding challenges are keeping you awake at night, you can count on MediBill MD’s tailored ASC billing services. Our team of AAPC-certified coders works around the clock to file clean claims for you.
