Factor VIII inhibitor profile (Nijmegen-Bethesda & ELISA)
Our laboratories employ a modified Nijmegen-Bethesda assay which uses buffered normal plasma and dilutions in 4% BSA to reduce pH drift and maintain constant protein concentration, that can otherwise falsely suggest the presence of a weak inhibitor.
FVIII antibodies can also be detected using indirect enzyme-linked immunosorbent assay (ELISA). FVIII antibodies in patient sera, whether inhibitory or 'immune', are captured in microtitre plates coated with recombinant FVIII. Unbound material is then washed off and a solution of antibody to human immunoglobulin that is conjugated to an enzyme is added to ‘tag’ onto any captured FVIII antibodies. Unbound conjugate is washed off and a substrate for the enzyme is added, the product of the enzyme-substrate reaction being coloured. Colour intensity is in direct proportion to the degree of conjugate-binding, itself proportional to the amount of FVIII antibody capture. The assay is not quantitative and is reported as either positive or negative based on whether the colour intensity exceeds a kit-specific cut-off value.
150µL and 1mL x 2 aliquots separately
Internal requests: please refer to EPR label
The samples should be analysed or manipulated & stored in the laboratory within 4 hours of venepuncture. Please ensure citrate sample tubes are filled exactly to the fill-line as underfilling creates a dilution error and leads to inaccurate results.
North Wing - 4th and 5th Floors
Westminster Bridge Road
London SE1 7EH
Laboratory opening times
Last updated: 09/03/2017