Laboratory diagnosis of 2009 H1N1 influenza A virus.

The emergence of 2009 pandemic influenza H1N1 has necessarily led to the rapid evolution of sensitive, specific, and high-throughput molecular diagnostic assays for this virus at the same time that clinical laboratories attempt to cope with increasing demands in the setting of resource limitations. This situation has given rise to testing algorithms focusing on priority, clinical relevance, and appropriate surveillance. We describe the current state of understanding around diagnostic testing and laboratory detection of 2009 H1N1 influenza A virus.