I have searched unsuccessfully looking for an answer in regard to purchased diagnostic tests for "stress scho". We have a number of practices serviced what I call the "Scan Van." The tech does the test and the reading is done by a specialist in that field. In short, the ordering physician pays the scan van company for services performed at the office. My question pertains to the stress echo codes 93350 and 93351. Neither of these codes seem to fit the criteria of modifier TC, as the physician only ordered the test, scan man performed the test with his equipment and a offsite cardiologist read the test. The scan van fee ticket only has 93350 on it and the physician then added 93306 (wrong)! When I contacted the owner of the scan van, he response was to bill 93351, 93320 and 93325. (Medicare patient)