Assay for rapid detection of cerebrospinal fluid leaks

An improved method of performing neurosurgery comprising

• (a) performing a neurosurgery on a subject
• (b) and during and/or subsequent to the neurosurgery, determining, or having determined, if a blood sample, a serum sample, an otorrhea sample, a rhinorrhea sample, or a drainage from a spinal suture area of the subject contains cerebrospinal fluid, thereby identifying the subject as having a cerebrospinal fluid leak, by a method comprising:
• detecting if cerebrospinal fluid (CSF) is present in the liquid sample from the subject by
• a) distributing the liquid sample on to a sample pad of a lateral flow device which comprises, in lateral flow sequence:
• a sample pad, a conjugate pad, a binding portion, and an absorbent pad, so as to permit the sample to flow along the lateral flow device;
• and wherein:
• (i) the conjugate pad thereof, downstream in lateral flow from the sample pad, comprises both (A) and (B) thereon, wherein:
• (A) is a first plurality of transferrin-binding antibodies conjugated to a first plurality of nanoparticles, and
• (B) is a plurality of lectin molecules conjugated to a second plurality of nanoparticles;
• (ii) the binding portion thereof, downstream in lateral flow from the conjugate pad, comprises the following separate domains:
• a. a domain which comprises a second plurality of transferrin-binding antibodies which are adhered to a surface of the lateral flow device;
• b. a dried blood serum domain reagent adhered to a surface of the lateral flow device;
• b) determining an intensity of an optical signal present at domain (ii)(a) and also at domain (ii)(b);
• c) calculating an optical value, wherein the optical value is determined as =(T1 intensity)2×(T2 intensity), wherein T1 intensity is the optical signal intensity at domain (ii)(a), and T2 intensity is the optical signal intensity at domain (ii)(b), and determining if the optical value is above or below a pre-determined cut-off value for the lateral flow device,
• wherein if the optical value is above the predetermined cut-off value for the lateral flow device then the liquid sample is identified as containing cerebrospinal fluid, and wherein if the optical value is below the pre-determined cut-off value for the lateral flow device then the sample is identified as not containing cerebrospinal fluid, and
• where CSF has been detected as present in the sample, identifying the subject as having a cerebrospinal fluid leak, and, optionally, conducting further surgery to fix said leak.