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Surgical Modifiers: Part 1
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When it comes to surgical procedures, modifiers convey to the payer a detailed story of exactly what occurred during the operative session. And since surgical claims cannot be paid correctly if submitted incorrectly, it’s imperative to get the modifier story straight the first time. As such, this series of articles will detail exactly which modifier should be used in each surgical condition.

Types of Modifiers

There are two types of modifiers:

1. CPT or Level I modifiers, which are two-digit numbers ranging from 21 to 99.

Modifier Definition
50 Bilateral procedure
51 Multiple procedures
53 Discontinued procedures
54 Surgical care only
55 Postoperative management only
56 Preoperative management only
58 Staged or related procedure or service by the same physician during the postoperative period
59 Distinct procedural service
62 Two surgeons
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period
79 Unrelated procedure or service by the same physician during the postoperative period
80 Assistant surgeon

2. Healthcare Common Procedure Coding System (HCPCS) or Level II modifiers, which are two-digit alpha or alphanumeric codes.

Modifier Definition
Upper left, eyelid
E2 Lower left, eyelid
E3 Upper right, eyelid
E4 Upper left, eyelid
RT Right eye
LT Left eye
GA Advance Beneficiary Notice on file
GY Deny the claim
GW Service rendered is not related to the hospice patient’s terminal condition
PA Surgery on wrong body part
PB Surgery on wrong patient
PC Wrong surgery on patient

HCPCS Modifiers –RT and –LT

Let’s begin with the modifiers recognized by all payers: –RT and –LT. One or the other should append any surgical CPT code. 

Example: For a laser peripheral iridotomy (LPI) performed on the right eye of a Medicare Part B patient, the correct claim submission is 66761–RT. CPT code 66761 Iridotomy/iridectomy by laser surgery (one or more sessions) has a 10-day global period for Medicare Part B. If an LPI is submitted on the left eye two weeks later, the correct claim submission is 66761–LT. Without appending modifiers –RT and –LT, the second claim could be denied as a duplicate claim submission and the second eye denied payment.

Modifier –50, Bilateral Procedure

When the same surgical procedure is performed on both eyes during the same surgical encounter, practices may append the surgical code with modifier –50.

Example: For a procedure on one vertical muscle in the right eye and one vertical muscle in the left eye, correct coding is either 67314–50 or a two line item (67314–RT and 67314–LT). Either way, payment should be 150 percent of the allowable — 100 percent of the allowable for the first eye and a 50 percent reduction of the full allowable for the second eye. Practices should never reduce the charge for the second eye, as the payer will automatically do that for you.

Note: Modifier –50 is not an ASC-recognized modifier. When submitting a claim for ASC payment, procedures should be reported as:

  • A single unit on two separate lines; or
  • A single unit with a “2” in the unit field.

A multiple procedure reduction equal to 50 percent of the payment for the second procedure applies to ASC payments, too.

Modifier –51, Multiple Procedures

You might need to rethink the way you code when multiple procedures are performed. Keep in mind that:

  • Surgeons tend to list the primary procedure first.
  • Staff tends to list the procedure with the highest office charge first.
  • Correct coding practice is to list the procedure with the highest allowable first. This may vary by payer.

Example: For a pars plana vitrectomy with lensectomy performed in the left eye, CPT code 67036–LT is listed first if the code has the highest allowable. CPT code 66850–51–LT should be listed second, as it has a lower allowable amount.

Like the payment rules for modifier –50, procedures appended with modifier –51 pay 100 percent of the allowable for the primary procedure and 50 percent for the second through fifth procedure. Each procedure after the fifth requires documentation.

Do not use modifier –51 with E&M or eye codes, or with add-on codes such as +67331 Strabismus surgery on patient with previous eye surgery or injury that did not involve the extraocular muscles. List separately in addition to coding for the primary procedure.

Example: Here’s how the incorrect use of modifier –51 can result in a loss of payment.

CPT code 65756–LT Keratoplasty (corneal transplant); endothelial
CPT code +65757–51–LT Backbench preparation of corneal endothelial allograft prior to transplantation

Appending modifier –51 above would incorrectly reduce payment of add-on code +65757 by 50 percent.

In fact, you may not need modifier –51 at all, as most payer systems are sophisticated enough to see that more than one procedure is performed in the same operative session. Look closely at your remittance advice from the payer. If you’ve submitted the claim with modifier –51 and the payer has left it off, it is no longer needed.


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About the author: Sue Vicchrilli, COT, OCS, is the Academy’s coding executive and the author of EyeNet’s “Savvy Coder” column and AAOE's Coding Bulletin, Ophthalmic Coding Coach and the Ophthalmic Coding series.

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