Febrile seizures are the most common form of convulsions, occurring in 2?5% of children. In the approach to a convulsing febrile patient, discovering the cause of fever and excluding central nervous system infection, serious electrolyte imbalances and other acute neurologic illnesses are essential. History and physical examination may be helpful. The purpose of this study was to evaluate significance of laboratory diagnostic tests other than cerebrospinal fluid examination in first febrile seizures of children. In a descriptive study, medical records of 139 children with first febrile seizure, admitted between March 2004 and August 2005 to Yazd Shaheed Sadoughi Hospital, were evaluated on all laboratory diagnostic done tests (other than cerebrospinal fluid examination), classification of laboratory tests results (normal, outside of normal range, or significantly abnormal), number of significant abnormal tests not predicted by history and physical examination, change in management plan based on biochemical abnormalities and type of febrile seizure. Febrile seizure type was complex in one-third of patients. The number of laboratory tests performed was 9.24 ? 2.4 (range one to 16). Significantly abnormal test results were seen in 12% of patients. Patients less than one year old and those with complex febrile seizures had the greatest number of significantly abnormal test results. Significantly abnormal tests results not predicted by history and physical examination were seen in three cases (one with asymptomatic hypocalcemia and two with urinary tract infection), all of whom were less than 1 year old. Routine blood chemistry analysis is not necessary in children with febrile seizures and only should be ordered based on the patient's condition or medical history.
