Ultrasound-enhanced latex immunoagglutination test (USELAT) for detection of capsular polysaccharide antigen of Neisseria meningitidis from CSF and plasma.
OBJECTIVE
An ultrasonic instrument, the Immunosonic, was used to evaluate ultrasound-enhanced latex immunoagglutination testing (USELAT) for detection and serogroup determination of Neisseria meningitidis in clinical specimens.


METHODS
Eighty-two CSF and EDTA blood specimens from patients with suspected meningococcal disease (MD) were tested by USELAT. Results were compared with routine laboratory tests for confirmation of MD and discrepant results were resolved by analysis of further laboratory and clinical data.


RESULTS
Using the Wellcogen Bacterial Antigen Kit, USELAT was positive in 20 (24%) specimens. The resolved sensitivity of USELAT was 49% compared with 67% for PCR. There were no discrepancies between serogroups indicated by USELAT and serogroups confirmed by PCR or culture grouping.


CONCLUSIONS
Although USELAT could be performed in laboratories without facilities for PCR testing, a specific ultrasonic instrument is necessary and some experience is required in interpreting results. The lower resolved sensitivity makes USELAT unsuitable as a stand-alone rapid test, and it added little value to standard laboratory culture with PCR testing.
Porritt
Robert J
RJ
Department of Microbiology and Infectious Diseases, South Western Area Pathology Service, Sydney, NSW, Australia. rporritt@bigpond.com
Mercer
Joanne L
JL
Munro
Rosemary
R
D016470:Bacteremia / Q000175:diagnosis; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D007841:Latex Fixation Tests / Q000379:methods; D008585:Meningitis, Meningococcal / Q000175:diagnosis* / Q000276:immunology; D009345:Neisseria meningitidis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D011135:Polysaccharides, Bacterial / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014465:Ultrasonics; D014463:Ultrasonography / Q000295:instrumentation*
D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial