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Common ASC coding errors: Orthopedics, gastroenterology and ophthalmology

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There are complex areas of coding in all ASC specialties which may lead to errors.

Coding errors for any specialty may lead to under-coding, which may adversely affect the ASCs financial health, or up-coding, which puts the ASC in jeopardy of non-compliance. The three most common specialties performed in ASCs are orthopedics, gastroenterology and ophthalmology. This article, the first in a two-part series, addresses some frequently found coding errors for each of these specialties.


Knee arthroscopy (single compartment) — In most cases, for multiple procedures performed within a single compartment, only the most complex procedure described in the procedure note should be coded. If a patient has a meniscectomy and synovectomy in the medial compartment of the knee, only a single code may be used — in this case, 29881 (meniscectomy) — as it is considered more complex than 29875 (synovectomy).

Knee arthroscopy (different compartments) — When the procedure note describes multiple procedures in different compartments of the knee, the most complex procedure in each compartment may be coded. If a patient has a meniscectomy in the medial compartment and synovectomies in the lateral and patellofemoral compartments (provided it is a major synovectomy of at least two compartments, not just a clean-up procedure and meets the requirements for a separate diagnosis), you may code both 29881 and 29876 with no need for a -59 modifier.

Example: A medial compartment meniscectomy and lateral and patellofemoral compartment synovectomies were performed arthroscopically in the right knee. Proper coding would be:

  • 29881-RT – excision of the meniscus medial compartment, and
  • 29876-RT – synovectomy lateral and patellofemoral compartments.

Hardware/implant removal (fractures) — CPT code 20680 may only be used once per fracture, despite the number of implants removed or incisions needed to remove the hardware.

Tendon grafts with anterior cruciate ligament repairs — Coders may not use code 20924 for harvest of graft from a distance with code 29888 for ACL repair unless the graft is harvested from the opposite knee or from either ankle.


Colonoscopy (screening versus diagnostic) — If there are any symptoms or indications listed in the procedure note, then it is no longer considered a screening procedure even if the provider states it is a screening.

Example: Indication or preoperative diagnosis states screening and chronic diarrhea. If it is significant enough to be listed as an indication/preoperative diagnosis, then the coder should use the appropriate diagnostic colonoscopy code. Further clarification and/or corrected procedure note from the provider may be needed for clarification.

Medicare screening colonoscopies — As indicated above, when a colonoscopy is scheduled as a screening colonoscopy and no indications or preoperative diagnoses are indicated, the appropriate G-code should be used. If any other procedures are performed (e.g. biopsy, polyp removal) then the coder should use the appropriate CPT code for the actual procedure. On the Medicare claim, it is important to list the screening diagnosis code first followed by the polyp or other applicable diagnosis code(s).

Specific payer requirements — Coding errors may occur if the coder does not know specific carrier requirements for coding specific procedures. This is especially true for screening colonoscopies. Different payers have different requirements and interpret the U.S. Multi-Society Task Force on Colorectal Cancer recommendations differently. There is also some leeway for Medicare payers in interpreting screening versus diagnostic colonoscopies which may involve a patient co-payment.

Example: Many commercial payers and Medicare Advantage plans consider a history of adenomatous polyps as a symptom and therefore rule out the patient ever having another co-payment-free screening procedure.


Complex cataract removal — CPT 66982 is defined as "extracapsular cataract extraction removal with insertion of intraocular lens prosthesis (one stage procedure), manual or mechanical technique (e.g., irrigation and aspiration or phacoemulsification), complex, requiring devices or techniques not generally used in routine cataract surgery (e.g., iris expansion device, suture support for intraocular lens, or primary posterior capsulorrhexis) or performed on patients in the amblyogenic developmental stage."

Documentation is key to demonstrating the complexity of the case. It is not the difficulty or the length of time needed to perform the procedure but whether it is a pediatric case or the case requires the use of special instruments that supports the use of 66982. If the documentation in the procedure note includes any of the following conditions, then a complex cataract repair should be coded:

  • miotic pupil that will not dilate sufficiently and requires the use of special instruments
  • multiple sphincterotomies
  • IOL requires additional support, such as a capsular tension ring or intraocular sutures
  • implantation of an IOL in a pediatrics case
  • mature cataract requiring the use of retractors or Malyugin ring

Billing separately for IOL used in a cataract extraction procedure — When coding any of the cataract extraction or other procedures involving IOLs (66982 through 66986) to Medicare, these codes include the insertion of an IOL in the procedure. These CPT codes include $150.00 reimbursement for the IOL. Medicare will pay the same amount for cataract extraction with A-C IOL insertion that it pays for cataract extraction with conventional IOL insertion. The only time V2632 (conventional or A-C IOL) can be coded separately is when the procedure is performed in a provider’s office.

However, there are two lenses that can be coded for Medicare patients. The astigmatism-correcting lens (e.g., Toric) is billed with V2787 and the presbyopia-correcting lens (e.g., Restor) is billed with V2788. When billing for these lenses, remember to allow a $150.00 credit already included in the Medicare allowances for these procedures. Commercial payer policies may vary.

Part II

Part II of this two-part series on coding errors in the ASC will focus on two additional specialties: podiatry and ENT. This second part will also provide generic coding hints applicable to most specialties.

Caryl Serbin, RN, BSN, LHRM (, is president and founder of Serbin Medical Billing, an ASC revenue cycle management company. Serbin Medical Billing's primary objectives are to provide the best coding, billing and accounts receivable management services available to ambulatory surgery centers (hospital joint-venture, corporate-owned or independent) and anesthesia providers. Serbin has been a leader in the ASC industry for 30 years. She was the founder of the first ASC-specific billing company.


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