[Neonatal infections. Diagnostic markers of infection].

Infections are highly prevalent in the neonatal period. Unfortunately the symptoms of infection are non-specific and are seen in other neonatal diseases as: respiratory distress syndrome, metabolic diseases, intracranial hemorrhages. Diagnosis is based on the clinics, microbiologic tests and laboratory markers of infection. Considering the high mortality and serious morbidity associated with neonatal sepsis, a diagnostic marker with a very high sensitivity and negative predictive value approaching 100% is desirable. Unfortunately there is no laboratory marker that has all of the characteristics of ideal infection marker. Procalcitonin, interleukins 6 and 8, CD 11b are early, sensitive markers of infection. C- reactive protein is a late specific marker of infection. CD 64 is the most sensitive marker of late, nosocomial infection. Serial measurement of infection markers will certainly improve the diagnostic sensitivity of these tests, because in most circumstances it is not certain at which stage of the infection the specimen should be taken for analysis. In addition, the use of multiple markers, in particular, combining an early sensitive marker with a late specific test will further enhance the diagnostic accuracy of these mediators in identifying infected cases.