Friday, January 29, 2016 - 08:00am Categories:
Medical Provider News Archive

WSI recently changed the standard for billing a unilateral procedure performed bilaterally in order to align with CMS.

A bilateral procedure occurs when a physician performs a unilateral procedure bilaterally, i.e. on both sides of a paired organ, during the same operative session. The proper billing protocol is to bill the bilateral procedure as one line, with one unit, and modifier 50 appended.

A bill not meeting the above criteria will deny with new WSI Reason Code 231:

This charge is denied because modifier 50 was used incorrectly per WSI guidelines. Please review fee schedule requirements for billing bilateral procedures on WSI website at Please resubmit the corrected bill for services rendered. The patient may not be billed for this reduced or denied charged.

A provider should not bill a modifier LT or RT in place of modifier 50, as these modifiers solely identify a service rendered on one side of a paired organ and do not result in an increase of payment. In addition, a provider should not bill modifier LT or RT on the same service line as modifier 50.

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