Bio-Rad Bio-Plex Software® Upgrades and Conversions - Manual (Page 113)

Bead Count
101
Bead Count
The Beads field in the Run Protocol window lists the number of beads to be
detected before a reading is complete. Note that this number can be beads
detected per region or total beads detected, depending on the pulldown
selection.
If you select per region as the counting method, you can enter a number
between 1 and 10,000 in the Beads field. For most assays, including the
Bio-Plex cytokine assay, we recommend a value of 50 beads per region. This
ensures that at least 50 beads in each region will be acquired before sample
acquisition is complete. If the region has less than 25% of the specified beads
per region or there are fewer than 20 beads (whichever number is greater), a
low bead warning is triggered. If you specify a bead count that is less than 20,
then a low bead warning is triggered any time the bead count is less than the
specified number.
If you select total as the counting method, you can enter a number between 1
and 100,000 in the Beads field. Note that if you choose to measure total
beads, the instrument will stop acquisition as soon as it has acquired the total
number of beads in any combination of bead sets. If you are detecting
multiple analytes, this means that some bead sets may be under represented
in the final tally.
NOTE: For the Bio-Plex™ phosphoprotein assay, we recommend specifying
25 beads per region to avoid triggering a low bead count warning.
Sample Timeout
The Sample Timeout field works in conjunction with the Beads field to ensure
that a well reading does not continue for an extended length of time. If the
specified bead count in the Beads field is not reached for a particular well (that
is, because the well does not contain all of the selected analytes), the array
reader will continue the well reading until the time limit specified in the Sample
Timeout field. If no Sample Timeout is specified, a default time based on the
sample volume is used.
You can enter a time limit in seconds from 0 to 200, or make a selection from
the pulldown list. Select <none> or enter 0 if you want no time limit. The
Sample Timeout value for each well will be noted in the Raw Data table.
BioPlex_6.book Page 101 Friday, September 23, 2011 11:55 AM