Plasma and urine elastase alpha-1-proteinase inhibitor levels in neonatal urinary tract infection.
OBJECTIVE
To examine whether plasma or urine elastase alpha(1)-proteinase inhibitor (E-alpha(1)-PI) levels could be used as a diagnostic marker of urinary tract infection (UTI) in neonates.


METHODS
Plasma and urine E-alpha(1)-PI levels were measured by immunoassay in 23 neonates with UTI at the time of admission and 72 h after the onset of treatment and in 10 'normal' neonates (i.e. with trivial problems). Additionally E-alpha(1)-PI plasma levels were measured in 15 neonates with septicemia.


RESULTS
E-alpha(1)-PI plasma levels did not differ between normal neonates and those with UTI. Urine E-alpha(1)-PI levels were significantly higher in neonates with UTI on admission compared to normal neonates. A significant decrease in urine E-alpha(1)-PI levels was noticed 72 h after the onset of treatment in all but 2 neonates in whom infection persisted. In this study, we have found that the urine E-alpha(1)-PI concentration at a cutoff level of 48 microg/l had a sensitivity of 83%, a specificity of 90%, a positive predictive value of 95% and a negative predictive value of 69% for the diagnosis of neonatal UTI.


CONCLUSIONS
Elevated levels of E-alpha(1)-PI in urine seem to be a useful tool for the diagnosis of UTI in neonates (even in those that have already been started on antibiotics) and possibly a valuable marker for early recognition of treatment failure.
Bakakos
P
P
Neonatal Unit, First Department of Pediatrics, Athens University, Athens, Greece.
Messaritaki
A
A
Mandyla
H
H
Nicolaidou
P
P
Anagnostakis
D
D
D016470:Bacteremia / Q000097:blood / Q000652:urine; D002097:C-Reactive Protein / Q000378:metabolism; D004926:Escherichia coli / Q000254:growth & development; D004927:Escherichia coli Infections / Q000097:blood* / Q000652:urine*; D006801:Humans; D007231:Infant, Newborn; D007958:Leukocyte Count; D019272:Leukocyte Elastase / Q000097:blood* / Q000652:urine*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014552:Urinary Tract Infections / Q000097:blood* / Q000652:urine*; D000515:alpha 1-Antitrypsin / Q000652:urine*
D000515:alpha 1-Antitrypsin; C037741:alpha 1-antitrypsin-leukocyte elastase complex; D002097:C-Reactive Protein; D019272:Leukocyte Elastase