I know on the test results that IGM comes first, produced during acute phase, then IGG is lasting immunity. However, through the FFC Tests: - I'm positive on IGG for M. Pnuemoniae, neg for IGM - I'm positive on IGG for Parvovirus, neg for IGM. Here's my issue, they tell I have parvovirus, not M. Pnuemoniae. Why do I have one not both??? Or do I have neither since I don't have IGM? Thanks!