While recently reviewing claims, I noticed an area of “undercoding,” or coding for a lesser procedure than is documented in the medical record. Upon review, this particular issue also appears as a repeat offender of the Comprehensive Error Rate Testing (CERT) program on several Medicare Administrative Carriers’ (MACs) web sites. Improper coding of bilateral procedures can significantly reduce collections.

To properly identify what procedures can be billed as bilateral, consult the CMS website. In the search criteria, enter the HCPCS code and search for the payment policy criteria. Under the column for bilateral surgery, there will be a number from 0 to 3. The bilateral indicators are:

0 – Bilateral criteria does not apply

1 – Conditional bilateral

2 – Inherent bilateral

3 – Independent bilateral

If the HCPCS code has an indicator of 0, no increase in payment will be made with the use of a modifier. An example is CPT® 11100, Biopsy of skin, subcutaneous tissue and/or mucous membrane (including simple closure), unless otherwise listed; single lesion. An indicator of 0 designates this as a procedure that cannot be billed bilaterally. Most procedures on the skin are not bilateral procedures.

For an indicator of 1, the procedure is considered bilateral if the modifier 50 is present, and should be reimbursed by Medicare at 150 percent of the allowed amount. An example is 65220, Removal of foreign body, external eye; corneal, without slit lamp. If this procedure is performed on both the right and left eyes, reimbursement by Medicare should be increased. Remember to increase the charge on the claim in order to request additional payment.

An indicator of 2 designates the procedure as inherently bilateral. Therefore, the procedure itself indicates a bilateral procedure and already includes payment for both sides. CPT® 58956, Bilateral salpingo-oophorectomy with total omentectomy, total abdominal hysterectomy for malignancy, is one such code. Do not append modifier 50 to these codes.

The indicator of 3 is usually related to radiological procedures. These procedures can receive 100 percent reimbursement for each side when the modifier 50 is appended and the documentation supports the procedure. An example is CPT® 73725, Magnetic resonance angiography, lower extremity, with or without contrast material(s).  If performed on both the left and right sides, bill with modifier 50 and increase the payment to 200 percent of the allowed amount.

Remember that each payer may establish their own guidelines and choose not to follow Medicare’s instructions. Also, each carrier may prefer representation of a bilateral procedure differently on a claim. For example, while most MACs prefer the use of modifier 50 on one claim line, some carriers request appending modifiers LT and/or RT, either on 1 claim line or 2 lines. Some prefer the designation of 1 unit while others recommend 2 units. Check with your specific carriers to ensure compliance with each payers’ regulations.