Diagnostic potential of neutrophil elastase inhibitor complex in the routine care of critically ill newborn infants.
It has been suggested that determination of the neutrophil elastase alpha1-proteinase inhibitor complex (E-alpha1PI) improves the diagnosis of bacterial infection in newborns. We evaluated the use of E-alpha1PI measurements in 143 newborns, consecutively admitted to a tertiary intensive care unit, employing a new random access assay and a sampling procedure that minimises post-collection artefacts. The 95% range for noninfected newborns was 20-110 microg/l up to the 5th day of life and 20-85 microg/l thereafter. The sensitivity as to the diagnosis of culture-proven bloodstream infection was 80% for E-alpha1PI, 86% for the immature to total neutrophil ratio, 64% for C-reactive protein and 37% for the total white blood cell count. The corresponding specificity amounted to 97%, 85%, 85% and 86%, respectively. E-alpha1PI increases preceded elevations of C-reactive protein by 18 h. Like C-reactive protein, E-alpha1PI levels did not distinguish between bloodstream infection and non-bacterial inflammatory responses. Results of E-alpha1PI became available within 1 h of collection and usually 2-3 h before manual leucocyte counts.


CONCLUSIONS
Determination of neutrophil elastase alpha1-proteinase inhibitor levels yields diagnostic advantages comparable to those of manual differential counts but provide faster turnaround times.
Fischer
J E
JE
Department of Neonatology and Intensive Care Medicine, University Children's Hospital, Zurich, Switzerland. joachim.fischer@kispi.unizh.ch
Brunner
A
A
Janousek
M
M
Nadal
D
D
Blau
N
N
Fanconi
S
S
D015331:Cohort Studies; D016638:Critical Illness; D006801:Humans; D007231:Infant, Newborn; D019272:Leukocyte Elastase / Q000097:blood*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis*; D000515:alpha 1-Antitrypsin
D000515:alpha 1-Antitrypsin; C037741:alpha 1-antitrypsin-leukocyte elastase complex; D019272:Leukocyte Elastase