Most physicians use what is known as the rapid influenza diagnostic test at he point of care, in other words, in their office or clinic. They can detect influenza A or B but can not distinguish the subtype (i.e., the H and N designation). Therefore this test can not distinguish between seasonal influenza and the novel H1N1 influenza A virus (aka swine flu). The other problem with this test is that it is not particularly sensitive, which means it can give what is known as false negative results (i.e., a negative result even though the person might actually be infected). The definitive test to identify swine flu is a molecular test called the real time reverse transcriptase polymerase chain reaction (rRT-PCR) which, at this time is available at state health department laboratories and the CDC. The commerical laboratories have also developed tests to identify swine flu.