Bio-Rad Bio-Plex System Validation and Calibration Tools - Manual (Page 11)

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Section 8
Principle of Fluidics Validation
Principle
The fluidics system of the Bio-Plex suspension array reader requires routine
maintenance to prevent clogging and other malfunctions. Strict adherence to the
maintenance procedures is mandatory for optimal instrument performance. An
assessment of the integrity of the fluidics is automatically performed in the
Fluidics Validation procedure. In the fluidics validation test, a sample of beads is
analyzed followed by a sample of buffer to assess the carryover of beads from
one well to another. This procedure should be performed once per week to
ensure that assay results are not adversely affected. The fluidics path, including
the sample needle must be completely free of debris and excess beads for
optimal array reader performance.
Impact on Assay Performance
If a system is exhibiting a high level of carryover, due to valve malfunction or
partially clogged sample needle, a significant percentage of beads may be carried
over from one well to another. This phenomenon may adversely affect the median
fluorescent intensity values. For example, if a well with a high median fluorescent
intensity (FI) is read immediately prior to a well with a low median FI, the signal in
the well with the low fluorescent intensity may shift upward. This phenomenon
only occurs in extreme cases since the median fluorescent intensity statistic is
robust and is not easily shifted by the introduction of a population of beads with a
significantly different median FI.
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