Table of Contents
Advertisement
10
Appendices
Appendix E: System Overview & Principles
The table and test strip are pulled
into the instrument after the correct
placement of the test strip is
confirmed. The table then moves
completely into the instrument
closing the shutter. All test pads are
read simultaneously at all six
wavelengths. The test and
reference readings are then used to
determine presence and/or amount
of each constituent in the urine
sample.
Each time a cassette is read, the
instrument positions the table
correctly and checks the electronics
and signals. It then takes reference
readings of the white calibration bar
on the test table. The readings are
taken at two wavelengths (525 nm
and 845 nm) and are then used to
calculate the sample readings.
The table and cassette are pulled
into the instrument where the
presence of the cassette is
confirmed. The table then pulls
completely into the instrument
closing the shutter and the
cassette "read area" is scanned at
two wavelengths. The test and
references readings are then used
to determine presence or absence
of hCG the urine sample.
Differences between the Human
Eye and Instrumental Optics
There are inherent differences
between the colors that are
perceived by the human eye and
that are detected by any instrument
optical system. The human eye is
capable of detecting minute
differences in shade and very small
areas of color; whereas instrument
optical systems are less sensitive
to such small changes. Conversely,
instrument optics are capable of
detecting certain colors that are
masked by or blended with other
colors to the human eye.
For this reason, exact agreement
between visual results and
instrument results might not be
found. However, agreement is
generally within one visual color
block or reported level and is equal
to or better than the agreement
between two visual readers.
10-13
Hide quick links:
Advertisement
Table of Contents
