In our office we perform urine tests for drug testing. We are a CLIA waived facility and are requried to use the QW modifier on urinalysis CPT codes. Suddenly, a few months ago Medicare and commercial carriers started denying stating "Modifer is not appropriate". . We have contacted Medicare and several commercial carriers and they can not explain what is happening. On some denied claims, the insurance company will send us an EOB paying for the codes with the QW modifier that they just denied...

We have not been able to find any changes to usage for this modifier.

Any ideas?