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-alpha1-proteinase inhibitor complexes were compared in the diagnosis of neonatal sepsis and bacterial infect ions 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 i ntensive care unit with positive bacterial cultures were analysed for both analytes. Two adults with long-term infections were followed up o ver a period of 28 and 65 days respectively. The results showed that i n 17 cases of confirmed neonatal sepsis within the first 24 hours of l ife, c-reactive protein levels were undetectable in 16 cases, one leve l of 13 mg/l being recorded. All had elevated elastase-alpha1-proteina se inhibitor concentrations. Of the remaining 15 samples, 13 were norm al and 2 were borderline for this analyte. C-reactive protein levels w ere between 5 and 10 mg/l in 5 cases and undectable in the remaining 1 0 samples. Those neonates with detectable c-reactive protein levels we re between 20 and 72 hours old with a gestational age greater than 31 weeks. C-reactive protein was undetectable in samples taken at the sam e time interval after birth from full-terms babies with a gestational age of 41-42 weeks, even in confirmed cases of neonatal sepsis. In adu lts, 64/68 samples showed both elevated c-reactive protein and elevate d elastase-alpha1-proteinase inhibitor, the remaining 4 samples being elevated for c-reactive protein and normal for elastase-alpha1-protein ase inhibitor. Three of these four patients had a pronounced leukopeni a. Although the diagnostic value of a single determination of either a nalyte was sufficient and similar in both cases, the time course of ea ch was different during the course of illness and treatment, so that t he correlation between c-reactive protein and elastase-alpha1-proteina se inhibitor, although statistically significant (p = 0.01) was relati vely low (r = 0.312, n = 115). From the results it can be shown that t he analyte of choice for neonatal sepsis within the first 3 days of li fe is elastase-alpha1-proteinase inhibitor. In older infants and adult s, c-reactive protein is preferable, as it is quicker to determine, ca n be performed in most clinical chemistry laboratories and is of simil ar diagnostic value.