A new nephelometric assay for beta-trace protein (prostaglandin D synthase) as an indicator of liquorrhoea.
OBJECTIVE
To determine the sensitivity and specificity of a nephelometric beta-trace protein assay for the diagnosis of liquorrhoea.


METHODS
One hundred and forty clinical samples with suspected liquorrhoea were analysed by a newly developed nephelometric assay. An established electroimmunoassay served as a reference method. The sensitivity and specificity of the beta-trace nephelometric assay were calculated by a 2x2 contingency table for 10 different versions of a dichotomised nephelometric variable. In 52 patients (79 samples), the nephelometric findings were validated by referring to the clinical diagnosis based on the course of the disease, imaging techniques, and surgical inspection.


RESULTS
Given a specificity of 100%, a beta-trace protein concentration of 6 mg/l or higher in a sample indicated liquorrhoea with a sensitivity of 92% compared with the reference method and of 93% compared with the clinical evaluation. The relation between the electroimmunoassay and the nephelometric assay was highly significant (p<0.001).


CONCLUSIONS
The nephelometric beta-trace protein assay is a simple and rapid method for the detection of liquorrhoea with high sensitivity and specificity and may facilitate the diagnosis of fistulas leaking CSF.
Petereit
H F
HF
Klinik und Poliklinik für Neurologie und Psychiatrie, Josef-Stelzmann-Strasse 9, D-50924 Köln, Germany. hela-petereit@medizin.uni-koeln.de
Bachmann
G
G
Nekic
M
M
Althaus
H
H
Pukrop
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002558:Cerebrospinal Fluid Otorrhea / Q000134:cerebrospinal fluid* / Q000175:diagnosis / Q000201:enzymology* / Q000209:etiology / Q000601:surgery; D002559:Cerebrospinal Fluid Rhinorrhea / Q000134:cerebrospinal fluid* / Q000175:diagnosis / Q000201:enzymology* / Q000209:etiology / Q000601:surgery; D002648:Child; D004568:Electrodiagnosis / Q000592:standards; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000592:standards; D019746:Intramolecular Oxidoreductases / Q000134:cerebrospinal fluid*; D054834:Lipocalins; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods* / Q000592:standards; D012680:Sensitivity and Specificity; D013997:Time Factors
D054834:Lipocalins; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase