I have collected blood, trachea and kidney samples from suspected field with IBV. I have done qRT-PCR for blood samples and they were negative to IBV. I was woundering, should I do the test on the tracheas samples? Is it possible to get positive results in trachea with negative results in blood for the same sample source? Does the period of sample storage affect the Ibv RNA isolation?

Note: the samples were collected from fully suspected Ibv fields.

Thanks for any reply