This test is not intended to replace a professional inspection by an accredited commercial laboratory. The lead test kit will detect high levels that exceed government guidelines but no guarantees are intended or implied.
Other toxic metals can give a positive response. If copper or bismuth is present, it is indistinguishable from lead in this test. This is of little concern as these elements are not usually present in the items that can be tested with the kit. If the items were properly manufactured, they would not release these toxic metals in amounts that would give a positive response using this testing procedure.