Predictive values of beta-trace protein (prostaglandin D synthase) by use of laser-nephelometry assay for the identification of cerebrospinal fluid.
OBJECTIVE
beta-Trace protein (beta-TP) is an immunological marker for the detection of cerebrospinal fluid traces. The aim of the study was to evaluate the predictive values of a new research assay for beta-TP.


METHODS
A total of 154 specimens from patients with otorrhea or rhinorrhea were investigated for cerebrospinal fluid (CSF) by use of a laser-nephelometric assay for beta-TP. Samples were obtained between January 1994 and November 2000. A sample was reported to be positive for CSF when the beta-TP concentration was more than 6 mg/L. Case evaluations were performed retrospectively and tabulated for indication, clinical course, additional investigations, surgical procedure, and follow-up.


RESULTS
beta-TP was detected in 16 specimens; 138 samples were negative for beta-TP with a value less than 3 mg/L. One sample was suggestive of CSF traces at 4.6 mg/L. In correlation with the clinical course, the intraoperative findings, intraoperative visualization with sodium fluorescein, high-resolution computed tomography of the paranasal sinuses or the petrous bone, computed tomographic cisternography, magnetic resonance imaging, and radionuclide cisternography, there was no false-positive result. On four occasions, false-negative results occurred, with an overall accuracy of 0.974. The beta-TP test had a negative predictive value of 0.971 and a positive predictive value of 1.


CONCLUSIONS
Analysis of betas-TP via the nephelometric assay is a valuable and reliable test in cranial base surgery for the identification of CSF.
Bachmann
Gregor
G
Department of Otorhinolaryngology, University of Northern Norway, Tromsø, Norway. gregor.bachmann@rito.no
Petereit
Hela
H
Djenabi
Uta
U
Michel
Olaf
O
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002558:Cerebrospinal Fluid Otorrhea / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D002559:Cerebrospinal Fluid Rhinorrhea / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005189:False Positive Reactions; D005947:Glucose / Q000134:cerebrospinal fluid; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000134:cerebrospinal fluid*; D007834:Lasers; D054834:Lipocalins; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D054834:Lipocalins; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D005947:Glucose