NEW INSTRUMENTATION PREVIEW
The CLINITEK 200+ Urinalysis Analyzer
The CLINITEK 200+ analyzer is the
latest addition to the series of analyzers from Ames Diagnostics (Elkhart,
Ind). The 200+ combines the features
of the CLINITEK 200' and the CLINITEK 1002 into a semiautomated
benchtop instrument that is designed
to read only Ames urine reagent
strips. A keypad has been added to
the 200+, allowing users to type patient identification, specimen clarity,
and color transparency information.
System Description and Basic
Operation
The CLINITEK 200+ is a freestanding,
reflectance-reading spectrophotometer that analyzes the color and intensity of light reflected from the reagent
area and then prints clinically meaningful results. A program card contains all of the information necessary
to read the reagent strips. Depending
on the strip used, the instrument can
measure levels of glucose, bilirubin,
ketone (acetoacetic acid), specific
gravity, occult blood, pH, protein,
urobilinogen, nitrite, and leukocyte
esterase.
All communications between the
operator and the instrument are
made through the keypad and a
two-line display. Specimens can be
processed in batches, individually, or
as statistics at a rate of about one
strip every 10 seconds. All results are
printed on an internal printer and can
be transferred to an 80-column printer
or to a computer through an RS-232C
port interface.
Instrument Calibration, Control,
and Maintenance
A halogen lamp illuminates 11 fiberoptic bundles. One of the small bundles carries light from the lamp to a
detector, where the light is measured
and the voltage that powers the lamp
is regulated. This ensures that a constant light output is maintained. The
remaining 10 bundles carry light to
the reagent areas that are positioned
under the read heads. A portion of
the light that strikes the reagent pad
is reflected onto a second set of fiberoptic bundles. The reflected light at
specific wavelengths depends on the
change in the pad's color and is directly related to the concentration of
the specific substance in the urine.
This light passes through a set of interference filters to a photodetector,
which converts the light into electrical
impulses.
The electrical impulses are processed and converted into clinical results that are printed on thermal-sensitive paper. The program card (which
replaces the programmable module
on the CLINITEK 200) programs the
instrument for wavelengths, error
messages, operating sequence, and
the algorithms needed to convert reflectance into clinical results.
The 200+ is calibrated by pressing
the "Cal" button, which prompts the
display of the "Place Cal Strip" function. The calibration strips furnished
with the instrument contain areas
with known reflectance valves. Like
regular urine strips, calibration strips
are inserted and read under all of the
read heads. After the calibration
readings are stored in the instrument,
the message "Calibrated" is printed.
If the instrument needs recalibrating,
"Daily Calibrate" is printed. The performance of the instrument and the
reagent strips should be checked at
the start of the day's run, whenever a
new bottle of reagent strips is used,
whenever the instrument operator
changes, or whenever test results are
not definite.
Ames recommends using CHEKSTIX (Ames Diagnostics) as a control;
however, any urine control that can
produce printed results for Ames
reagent strips may be used. The urine
specimen from any healthy individual
can be used as a negative control. All
control results should be documented
and retained, as required.
The 200+ analyzer's fixed platform,
movable blotter, and moving table
must be cleaned daily with warm water and mild detergent. Each part is
easily removed from the instrument
and should be rinsed thoroughly and
dried. The used reagent strips and
The CLINITEK 200+ semiautomated reflectance-reading urinalysis analyzer. Note the new keypad.
Laboratory Medicine Vol. 23, No. 8 August 1992 555
disposable cardboard container should
be emptied into an appropriate receptacle. The parts may be disinfected, if
required, by immersing them in a 2%
glutaraldehyde solution for 10 minutes
after cleaning with water and detergent. Cidex (Surgikos, Inc, Arlington,
Tex) in full strength or a 1:16 dilution
of Sporicidin (Sporicidin International,
Rockville, Md) are also acceptable disinfectants. Each part should be rinsed
and dried after soaking.
Sample Processing
Processing begins by pressing the
"Run" key, and then typing the identification number, level of specimen
clarity, and color by following the displayed menu prompts. The instrument will beep after a 10-second visual bar graph display, prompting the
operator to dip the strip in specimen
and place it on the loading station.
The rest of the analysis is automatic,
and new strips can be dipped and
placed on the instrument at 10-second intervals.
The movable blotter advances the
strip under the first set of fiber-optic
read heads, where the reflectance is
measured at appropriate wavelengths.
All reagent areas except leukocyte esterase are read under the first read
heads. The strip advances to the second fiber-optic read head where the
leukocyte esterase level is read. Results are then printed, and the strip is
automatically advanced and discarded
in the cardboard waste container.
The instrument will continue to
prompt and cycle for 80 seconds after the last strip passes under the first
read head. The visual and audio
prompts will stop if another strip is
not detected under the read head.
The strip advances for an additional
20 seconds, and if a strip is not detected, the instrument will go into
the standby mode. Eight specimen
color descriptions may be selected:
yellow, dark yellow, straw, amber, red,
orange, green, and other. The operator may also choose from five descriptions of transparency or clarity:
clear, SL (slightly) cloudy, cloudy, turbid, and other.
5 5 6 Laboratory Medicine Vol. 23, No. 8 August 1992
Conclusion
The CLINITEK 200+ reflectance-reading analyzer is designed for laboratories that perform moderate to large
urinalysis testing. Designed to read
only Ames urine reagent strips, this
instrument is easy to calibrate, operate, and maintain. The author found
no significant clinical differences between the results of more than 500
urine specimens tested on the CLINITEK 200+ and the results obtained
from visual reading, the CLINITEK
200, and the CLINITEK 100.—James
A. Jackson, MD, Department of Clinical Sciences, College of Health Professions, Wichita State University, Wichita, KS 67208-1595Q
References
1. Jackson JA, Campbell JL, Conrad ME. A
high speed urine reagent strip reader. Am Clin
Prod Rev. 1986;10:12-16.
2. Conrad ME, Jackson JA, Campbell JL. A
semi-automated urine chemistry analyzer Am
Clin Lab. 1991;7:10-12.