The limitations and usefulness of C-reactive protein and elastase-alpha 1-proteinase inhibitor complexes as analytes in the diagnosis and follow-up of sepsis in newborns and adults.

C-reactive protein and elastase-alpha 1-proteinase inhibitor complexes were compared in the diagnosis of neonatal sepsis and bacterial infections in adults on the intensive care unit. Both analytes were measured in the same sample immediately after receipt. EDTA-plasma samples (n = 115) from 28 neonates (gestational age 29-42 weeks) within the first 72 hours of life with suspected neonatal sepsis, 2 babies between 14 and 28 days old with B-streptococcus infections and 28 adults on the intensive care unit with positive bacterial cultures were analysed for both analytes. Two adults with long-term infections were followed up over a period of 28 and 65 days respectively. The results showed that in 17 cases of confirmed neonatal sepsis within the first 24 hours of life, c-reactive protein levels were undetectable in 16 cases, one level of 13 mg/l being recorded. All had elevated elastase-alpha 1-proteinase inhibitor concentrations. Of the remaining 15 samples, 13 were normal and 2 were borderline for this analyte. C-reactive protein levels were between 5 and 10 mg/l in 5 cases and undetectable in the remaining 10 samples. Those neonates with detectable c-reactive protein levels were between 20 and 72 hours old with a gestational age greater than 31 weeks. C-reactive protein was undetectable in samples taken at the same time interval after birth from full-terms babies with a gestational age of 41-42 weeks, even in confirmed cases of neonatal sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)