VALUE OF ANTIGEN QUANTITATION IN HEMOPHILUS-INFLUENZAE TYPE-B MENINGITIS

H. influenzae type b [Hib] meningitis was studied in 68 patients to evaluate whether quantitative determination of PRP [polyribosylribitol phosphate] in body fluids obtained at admission or measurement of the duration of its presence helped identify patients at risk for complications. Geometric mean admission PRP concentrations in CSF, blood and urine increased with severity of disease; individual values varied greatly. Measurements of the duration of antigenemia and antigenuria also varied widely and were best predicted by the admission or peak PRP concentration. The mean duration of antigenemia and antigenuria increased with severity of disease. The elimination half-life of PRP did not differ significantly with severity of hospital course, peak PRP concentration in blood or urine or patient age. Clearance from CSF could not be accurately assessed; PRP was detectable in only 6 or 41 patients in whom spinal fluid was obtained after the 8th day of hospitalization; all had complicated courses. Although latex particle agglutination assay is a valuable aid in rapid diagnosis of invasive Hib infections, the predictive value of antigen quantitation at admission and the determination of its duration in body fluids is limited by the wide range of observed values.