--is the polymerase chain reaction test, to see if various infectious agents are in your sera--this can be done for any number of viral or bacterial pathogens (often depends on how many the doctor ordered; I once had one done for almost everything in the human herpes virus class, cytomegalovirus, parvovirus, and a whole batch of bacterial agents in one blood draw--all negative).

It should say on the test results what agents were tested for--each usually gets a seperate results entry.

That elevated IgG tends to imply a longer-term response than high levels of the other antibody classes--and in the absence of other cancer markers, particularly if there's a negative immunofixation electrophoresis result, one would tend to think infectious agent.