False-positive beta-2 transferrin test not associated with a postoperative lumbar cerebrospinal fluid leak: A case report

Background: Lumbar laminectomy and fusion may be complicated by cerebrospinal fluid (CSF) leaks. Beta-2 transferrin (B2T) is a diagnostic marker for CSF that has been mostly studied in the context of cranial CSF leak, but its accuracy in diagnosing spinal leaks is less certain. Case Description: A 59-year-old male with chronic back pain and lumbar stenosis underwent a multi-level laminectomy and fusion with a watertight repair of incidental durotomy. Postoperatively, he developed a non-healing surgical wound and persistent high drain output with fluid testing positive for B2T. However, the patient had no clinical symptoms or signs of CSF leak and repeated wound exploration showed no leak. The wound became infected and, due to poor healing, the patient underwent a secondary closure with a negative pressure treatment dressing. Multiple intraoperative dressing changes did not disclose a CSF leak despite the fact that a repeat B2T in the wound fluid remained positive. Conclusions: This report describes a case of false-positive B2T in a patient after lumbar spine surgery. This case highlights the fact that a positive B2T measured in spinal wound fluid may not be diagnostic of a CSF leak. Possible sources of false-positive B2T laboratory results are discussed in this paper.