Comparative study of four tests of bacterial infection in the neonate. Total neutrophil count, CRP, fibrinogen and C3d

Abstract

In a prospective study, the diagnostic value of C3d serum levels was compared with that of neutropenia, hyperfibrinogenemia and raised CRP in generalized neonatal bacterial infections. Serum C3d was evaluated using a counter-immunoelectrophoresis technique following a step of removal of C3 split products. Twelve patients with septicemia, 8 patients with highly probable infection and 134 normal controls were included in the study. The sensitivities for neutropenia, hyperfibrinogenemia, raised CRP and positive C3d were 21, 45, 60 and 70%, respectively, with a significant difference between the sensitivities of neutropenia and positive C3d (p < 0.01). The specificities were found to be 99.2, 99.2, 100 and 97.7% respectively. Thus the C3d qualitative test appears to be as reliable as CRP in the diagnosis of neonatal bacterial infections.