G0431-qw with 12 units

When we are billing 12 units g0431qw, do we need to use 91 modifier for each addition drug class test?

G0431

Ok, I don't have an answer for you - sorry, but I am new to this code, we just started using this test in house and I am not getting paid for it by Medicare - so is it because I am not using 12 units?? I am by some other payors, but not others...is this my mistake..??
Sara

drug screen

I am also having problem with these drug testing codes. We do a multi not single drug strip, its run in a machine and I am having a problem now that changes went into effect. They won't pay for multi drugs. Any help on this would be very helpful.

G0431-qw

All payers paying single drug test for this code, Means with one unit, I am getting payment for one unit but we are performing multitest, Our claims were still pending, Waiting for the reply from insurance, Will update you guys, wish you good luck....