For 3days friend has nausea vomiting diarrhea.got iv at er today-blood test shows gastroenteritis.does viral show up in blood test?or just bacterial?

Well, the ER doctor: may have looked a clinical symptoms, history & examination in combination with a Complete blood count with differential (CBC with Diff). The CBC does not make a hard diagnosis but can be suggestive. For instance ^ lymphocytes might suggest a viral infection & ^ neutrophils might suggest a bacterial infection. A culture which was positive for a bacterial pathogen would be strong evidence