Infants in this 1 - to 3-month age group are differentiated based on Temperature Clinical appearance (ill - or well-appearing, as below) Laboratory results Ill-appearing febrile infants Febrile infants between 1 month and 3 months of age who are ill-appearing (eg, abnormal cry, lethargy, rectal temperature > 38.5° C) or who have risk factors for serious bacterial infection (eg, significant congenital anomalies, prematurity, technology dependence, unvaccinated) should be admitted to the hospital and have a WBC count with a manual differential, blood cultures, urinalysis and urine culture (obtained by catheterization, not an external bag), and lumbar puncture with CSF evaluation, including culture and, if available, PCR panel.