Bio-Rad Nonmagnetic Beads and Related Reagents - Manual (Page 34)

Possible Causes Possible Solutions
Greater than 30% bead loss
during conjugation
Poor pipetting technique
Inconsistent bead count values
Beads are too concentrated
Low MFI signal in assay
Conjugation failed
Problem with protein integrity
Conjugated beads have higher
background signal in assay than in
previous conjugation
Blocking step was skipped
following the conjugation
Coupling incubation time too long
32
Remove 50 µl of buffer at a time
from the bead pellet to minimize
bead pellet disturbance
Add 100% more storage buffer
Check validation procedure again
and repeat the conjugation if
necessary
Repeat conjugation with a new lot
of protein
Include the blocking buffer step
Use a consistent incubation time
during the coupling step