No code exists for bilateral breast ultrasound, but our doctors frequently perform and document bilateral exams. What is the required modifier for billing bilateral breast ultrasounds? We are currently billing 76641 LT and 76641 RT. Do you have any information that says we should be billing 76641 with modifier 50 instead of LT and RT? I don’t show anywhere that we should be reporting breast ultrasounds or radiology services with modifier 50 instead of LT and RT.


That depends on the individual payer. Code 76641 is reported for a limited unilateral breast ultrasound, and 76642 for a complete unilateral breast ultrasound. Technically it should be -50 when you do bilateral exams. But CMS allows x 2 or modifier 50, or RT and LT. Your MAC may have a specific rule, or you may want to choose a way, and then check your Explanation of Benefits (payment register). If you bill it one way and they deny it because of the modifier, then try another way. Other payers have their own policies. Some want -LT or -RT if you do unilateral, others will deny if you add that modifier; some want modifier 50 if you do bilateral, while others want it billed twice with RT and LT.


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