CAPILLARY PLASMA NEUTROPHIL ELASTASE ALPHA-1-PROTEINASE INHIBITOR AS INFECTION PARAMETER IN NEONATES

Raised plasma neutrophil elastase has been reported to be an early and effective marker of infection in neonates. In order to assess the fea sibility of implementing a rapid assay on capillary plasma, repeated h eel prick samples were taken in a series of 79 neonates with clinicall y suspected bacterial infection, comparing the elastase response with C-reactive protein (CRP) and with the band:mature neutrophil ratio. Ri ses in elastase were in agreement with rises in CRP, but were more fre quently manifest at onset of symptoms, showing elastase to be a more r apid marker of infection as previously described. However, 23% of elas tase measurements either failed due to haemolysis or coagulation or yi elded inexplicably high values. Comparison of simultaneous bilateral h eel prick values confirmed unacceptable variation, unlike comparison o f paired venous samples or venous and capillary samples from adults, i ndicating that capillary blood sampling in neonates produces an unpred ictable release of neutrophil elastase. Thus, in newborn infants sampl es for determination of elastase should be taken by venous punctures o r from indwelling catheters.