Laboratory studies
It is not recommended to perform routine serum labs when a child has a simple febrile seizure [49]. The labs that are performed should be based on the clinical presentation of the febrile illness. The Consequences of Prolonged Febrile Seizure Study (FEBSTAT), which enrolled 199 children from 1 month to 5 years of age with FSE, evaluated children for the presence of HHV-6A, HHV-6B, or HHV-7 DNA and RNA in serum [50,51]. Children that had central nervous system infection were excluded from this study, thus no subject had encephalitis. The study concluded HHV-6B infection is commonly associated with FSE, and HHV-7 infection is less frequently associated with FSE. Together the HHV infections accounted infection in one third of FSE subjects in the study [50]. The study did not detect HHV6B or HHV-7 DNA in the CSF of the 23 subjects who presented in FSE with documented HHV-6B or HHV-7 viremia.frequently have complex FS, and it is often difficult to differentiate children with intracranial infection from those without [48].