Cerebrospinal fluid leakage--reliable diagnostic methods.

Prompt diagnosis and early treatment of cerebrospinal fluid (CSF) leakage minimizes the risk of severe complications. In patients presenting with clear fluid nasal discharge it is important to identify the nature of the rhinorrhea. The CSF leakage may occur as post-traumatic, iatrogenic, spontaneous or idiopathic rhinorrhea. The differential diagnosis of CSF rhinorrhea often presents a challenging problem. The confirmation of CSF rhinorrhea and localization of the leakage may be diagnosed by CT, MRI cisternography and MRI cisternography in combination with single photon emission tomography or radioisotopic imaging. Although these methods allow estimation of the CSF leakage with high accuracy, they are expensive and invasive procedures. Therefore, biochemical methods are still used in the differentiation. Although the most common diagnostic method for screening CSF leakage is glucose oxidase, its diagnostic sensitivity and specificity is generally unsatisfactory. False negative results may occur with bacterial contamination and false positive results are common in diabetic patients. Glucose detection is not recommended as a confirmatory test. As such, other biomarkers of the CSF leakage, such as beta-2-transferrin (beta-2 trf) and beta-trace protein (betaTP) are necessary to identify and confirm of this condition.

A new nephelometric assay for beta-trace protein (prostaglandin D synthase) as an indicator of liquorrhoea.

OBJECTIVES: 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.

Clinical experience with beta-trace protein as a marker for cerebrospinal fluid.

beta-Trace protein is an immunological marker for the detection of cerebrospinal fluid traces. The aim of the study was to evaluate the predictive value of the beta-trace protein test. We investigated 145 specimens for cerebrospinal fluid using beta-trace protein. All case notes were retrospectively reviewed and tabulated for indication and procedure with focus on outcome. The specimens were analyzed by immunoelectrophoresis. beta-Trace protein was detected in 62 specimens and was absent in 83. In correlation with the clinical course, the clinical findings, the results of high-resolution computed tomography of the paranasal sinuses or petrous bone, computed tomographic cisternography, magnetic resonance imaging, indium 111-pentetic acid radionuclide cisternography, intraoperative findings, and visualization using sodium-fluorescein, there were no false-positive results. In 6 cases, a false-negative result occurred. The overall accuracy was 95.68%. The beta-trace test has a specificity of near 100% and a sensitivity of 91.17%. Analysis of beta-trace protein is a valuable test and has some advantages in comparison with the beta2-transferrin assay.