Hemocultura: although considered golden standard, sensitivity still is low, and the effectiveness of this disgnostic test depends on the used way of culture and it microorganism. Results false-positives can occur for contamination of the puno place; the form to prevent them is an adequate and aseptic collection. A positive result can be distinguished true from one for contamination punching themselves two different small farms at the same time, carrying through culture of the skin in the puno place or, still, repeating the test with interval of 12 the 24 hours. False-negative results occur when the mother uses antibioticoterapia in periparto, increasing in 12 times the risk of hemoculturas in the RN to result negativas20. Hemograma: leucopenia presence (20,000 leuccitos/mm3). The total number of neutrfilos 0,2 if correlates with one high risk of bacterial infection. It is important to remember that some not infectious situations, as fever materna, work of drawn out childbirth, administration of ocitocina intraparto, asphyxia, aspiration of mecnio, pneumotrax, convulsions, hemorrhage to intraventricular and hemoltica illness, is associates to the neutrofilia presence and increase of the index of neutrfilos; Protein C reactive (PCR): the PCR is a beta-globulina, synthecized for the liver after about eight hours of the beginning of an inflammatory stimulaton. In first and as the days of life its 10 normal sricos values are inferior mg/L and the 5 inferiors mg/L after this age.
This protein possesss some biological activities and present practically the same properties of a imunoglobulina enter the mechanisms of defense of the host. The presence of specific receivers for the PCR in the membrane of polimorfonucleares was demonstrated, being distinguished that these places would be different of the receivers of the Fc fraction of the imunoglobulinas. This fact shows the importance of this protein in the inflammatory reply, increasing the quimiotaxia and fagocitose of the bacteria for polimorfonucleares. Moreover, in the same way that the imunoglobulinas, the PCR is capable to activate the classic way of the complement.