Utilidad de la β2-transferrina y la proteína β-traza en el diagnóstico de fístula de líquido cefalorraquídeo

Résumé

Introduction Early diagnosis of cerebrospinal fluid (CSF) fistula minimizes the risk of severe complications for patients. A diagnostic approach consists in revealing the presence of CSF in nasal, ear, and surgical wound secretions. The aim of this work is to evaluate the usefulness of β2-transferrin (β2-Tr) and β-trace protein (p-βT) as markers for the diagnosis of a CSF fistula. Material and methods A total of 68 samples of nasal, ear, and surgical wound secretions were taken and analysed from 54 patients with clinical suspicion of a CSF fistula. β2-Tr and p-βT were determined in all fluids. The CSF fistula was diagnosed by clinical criteria and other diagnostic procedures. Sensitivity and specificity, as well as positive (PPV) and negative (NPV) predictive values, were calculated. The optimal cut-off point for p-βT was obtained using a ROC curve analysis. Results For β2-Tr, a sensitivity of 83%, a specificity of 96%, a PPV of 95% and a NPV of 86% were obtained. For the p-βT ROC curve analysis, the area under the curve was 0.981, with an optimal cut-off value of 1.14 mg/L. For this cut-off point, a sensitivity of 92%, a specificity of 95%, a PPV of 96%, and a NPV of 91% were calculated. The p-βT cut-off point obtained for 100% NPV was 0.64 mg/L. Conclusions β2-Tr and p-βT can be used as CSF fistula markers, since both proteins have high sensitivity and specificity diagnostic values. It is concluded that, ≥ 1.14 mg/L p-βT values are indicative of CSF fistula, and values ≤ 0.64 mg/L rules it out. Values > 0.64 and < 1.14 mg/L are not conclusive, and in these cases it would be necessary to determine β2-Tr.