It may not be a popular opinion, but when reporting a titer as the quasi-quantitative readout, I question the value of holding the signal of HPC and MPC to a tight precision standard as somewhat irrelevant given that the signal close to threshold at higher dilutions is driving the readout. In addition, without a calibrator it is hard to control some of the variability that may happen where the plate capacity is starting to approach saturation.
Of course the answer is a little different if using one of the signal/noise readouts, but I will let one of the advocates for that approach address from that perspective.
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Joleen White Ph.D.
AAPS 2024 Global Health Community Chair
Bioanalytical 101 Course Development
Head of Bioassay Development
Gates Medical Research Institute
Cambridge MA
[email protected]Disclaimer: Opinions expressed are solely my own and do not express the views or opinions of my employer.
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Original Message:
Sent: 10-02-2023 16:57
From: Anonymous Member
Subject: Inter-assay Precision for Anti-Drug Antibody Bridging Assay Acceptance
This message was posted by a user wishing to remain anonymous
Hi, I have a bioanalytical MSD bridging assay that uses Biotin-Extraction Acid Dissociation (BEAD) format for detection of ADA that is returning inter-assay precision slightly above 20% at HPC and MPC. The background of the assay is ~100 RLU and more variance is observed at the higher concentrations. The % inhibition is very consistent with HPC at ~80-90% and MPC at ~40-50% inhibition. There are no issues with intra-assay precision. Has anyone had any issues with this? Would this variance be an issue with FDA? Thanks in advance for any help.