Beta Trace Protein (?CSF leak)

Blood Sciences Test

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Specimen

Please collect minimum 0.5 ml into a white lid clear universal tube.

Test Usage

The leakage of cerebrospinal fluid (CSF) into nasal, oral or ear cavities or from a dermal sinus and its subsequent drainage from these cavities may be caused by trauma, intracranial surgical procedures, infection, hydrocephalus, congenital malformations and neoplasms. The most severe consequence of a CSF leak is microorganism contamination and the development of meningitis.

Epidemiology

• Prevalence – 70-80% are related to accidental trauma
  • 2-4% of head injuries result in CSF leaks
• Age – middle age for spontaneous leaks, newborn for dermal sinuses

Etiology

• Trauma
• Non-traumatic:
  • Surgery (usually spinal or neurosurgery)
  • Postoperative defect
  • Infection
  • Tumor obstruction
  • Congenital defects (at the base of the skull or at the end of the spinal cord)
  • Hydrocephalus
  • Spontaneous – no known defect or trauma

Pathophysiology

• Beta trace protein is found mainly in the CSF
• Interruption of the anterior cranial fossa floor allows leaks through the cribriform plate
• 80% of post-traumatic leaks occur in first 48 hours post-trauma

Clinical Presentation

• CSF leakage most commonly presents as otorrhoea or rhinorrhoea
• Patient may complain of salty or sweet taste; intermittent clear nasal discharge exacerbated by Valsalva maneuver

Diagnosis

• Indications for testing – presence of otorrhoea or rhinorrhoea; patient with recurrent episodes of meningitis
  • Laboratory testing
  • Chemical analysis (eg, Glucostix) of the fluid for glucose and protein is unreliable in determining the presence of CSF fluid
  • The presence of Beta trace protein indicates CSF leakage (high specificity and sensitivity)
  • False positives – chronic renal failure
• Imaging studies
  • Radiographic studies, with or without intrathecal injection of dye or radioisotope, are not always successful in demonstrating small or delayed CSF leaks
  • High resolution CT is initial study of choice
  • MRI
  • Cisternogram by CT or MRI

Turnaround time

Approx 1 month

Availability

Test referred to Neuroimmunology Unit, National Hospital for Neurology and Neurosurgery, Queen Square, London.

Specimen Labelling Procedure