Wiki Modifier 50 on Add-on Codes

[kellymb]

I know the AMA updated billing instructions in 2020 to indicate modifier 50 should not be reported in conjunction with add-on codes. Does anyone know why they made that rule? Why would it matter whether modifier 50 on a single line or two lines with the LT/RT modifiers are used to report an add-on code was performed bilaterally?

 

[csperoni]

While I cannot answer why, I can provide some anecdotal advice billing add on bilaterally. There is a specific add on code I need to bill bilaterally several times per month. While coding guidelines state it SHOULD be billed 38900-LT and 38900-RT, when I do, it gets denied 95% of the time for MUE edit. If I bill 38900-50 (even to Medicare), it pays properly. So this is one of the situations where I do not follow coding guidelines exactly, and receive correct payment first submission. If you are receiving denials billing an add on with -RT and -LT, I would try the "old" way.