Laboratory studies are an essential aspect in the management of children with grave diseases, helping to plan the therapeutic measures and to identify the disease. The most acute syndromes in pediatric emergency care are: coma, convulsions, dehydration, metabolic disequilibrium, hypovolemic or anaphylactic shock, a grave infection, chemical or drug poisoning. The laboratory tests that should be available within few minutes are blood cell count, blood and gas analysis, sodium, potassium, calcium, glucose measurements. The results of total proteins, serum creatinine and urea measurements, bleeding tests, analysis of blood smear, sedimentation rate, ALT, AST, osmolality, urinary electrolytes, creatinine and cerebrospinal fluid examinations should be available within sixty min. New accurate and rapid techniques and instruments facilitate the diagnostic and therapeutic approach to pediatric emergency.