BD CrystalSpec Guía Para La Utilizacion

8809791(0704).qxd 08/30/2004
CrystalSpec
User's Guide
English: pages 1 – 2
Français : pages 3 – 4
Deutsch: Seiten 4 – 6
INTENDED USE
The CrystalSpec™ Nephelometer is a battery-powered, portable device designed to measure the tur-
bidity of microbial suspensions equivalent to McFarland standards 0.5 through 4.0. The instrument can
be used for any laboratory procedure that requires inoculum density adjustments within this range.
SUMMARY AND EXPLANATION
The visual comparison of organism suspensions to turbidity standards is an accepted method of esti-
mating organism densities. The most widely accepted standard is the McFarland standard.
standard is prepared by adding barium chloride to aqueous sulfuric acid. The density of the resulting
barium sulfate precipitate can be used to approximate the colony count of a prepared suspension; e.g.,
McFarland 1 is the equivalent of approximately 3 x 10
sity measurements, including titanium dioxide
The instrumented measurement of turbidity relies on the ability of particles to scatter light while in
suspension. The measurement of this scattered light is referred to as nephelometry.
obtain an accurate density measurement, a reliable method of calibration must be used.
PRINCIPLES OF THE PROCEDURE
The CrystalSpec Nephelometer measures scattered light at a 90° angle of incidence. It is a solid state
instrument that uses a light-emitting diode as a light source and a photodiode detector. The instrument
was developed using bacterial suspensions at known concentrations (CFU/mL). Colony counts were cor-
related with McFarland units and the CrystalSpec instrument was programmed to display the mea-
surement in McFarland units. The calibration standards supplied with the instrument have been devel-
oped to assure an accurate calibration.
Before making a measurement on the CrystalSpec Nephelometer, the instrument is calibrated using
the supplied standards. To determine the McFarland equivalent of a microbial suspension, a tube is
placed in the reading chamber and the test button is pressed. The results are then displayed on the
LCD screen in McFarland units.
SPECIFICATIONS:
Range ...................... McFarland 0.5 – 4.0
Accuracy .................. + 0.2 McFarland Unit
Reproducibility ...... + 0.1 McFarland Unit
Battery .................. 9 V Alkaline
Battery Life ............ 1 Year (typically)
Precautions: in vitro Diagnostic
Read all instructions before use and follow precisely.
PROCEDURE
Materials Provided: CrystalSpec Nephelometer, including a CrystalSpec Calibration Blank (B),
CrystalSpec Calibration Standard (S), Low Volume Sample Adapter, and 9-volt battery.
Materials Not Provided: Ancillary culture media and equipment required to prepare a bacterial sus-
pension.
Instructions:
BATTERY INSTALLATION AND REPLACEMENT – Unpack the CrystalSpec Nephelometer and the 9 V
battery. Invert the instrument and remove the battery cover plate. Connect the battery and replace the
cover.
If replacing a discharged battery, press one of the buttons (either "Calibration" or "Test") for 3 sec
after discharged battery has been removed.
When a battery is initially installed, "T" will be displayed in the readout window while the internal
evaluation is in progress. This "T" will also appear when a discharged battery is replaced with a new
battery.
When installing a new battery, interrupting the contact before the battery clip is secure may cause
the "T" display to not continue to show. The unit should be functioning properly, but if in doubt, re-
install the battery per above.
The CrystalSpec instrument has an internal battery charge indicator. Along with sample readouts, a
reading from "B0" to "B5" is displayed at the far right edge of the window to indicate the level of
battery charge. A fully charged battery will display "B5", a battery needing replacement will display
"B0".
When the battery charge is so low that the integrity of the readings is compromised, "X" will be dis-
played and the battery will be completely discharged by the instrument. The meter will not operate
until the battery is replaced.
NOTE: Anytime a battery is replaced or the battery is disconnected from the unit, the instrument
must be re-calibrated.
CALIBRATION PROCEDURES – The CrystalSpec instrument requires no warm-up period and is ready
for calibration and immediate use. A CrystalSpec Calibration Blank (B) and CrystalSpec Calibration
Standard (S) are supplied with the instrument; use only these calibration standards for calibration.
Internal error checking is in place to assure proper calibration of the instrument.
The nephelometer has internal features that minimize the need for frequent calibrations.
Calibration needs to be performed only under the following conditions: (a) Any time the battery is
replaced or disconnected, (b) If the "E" message is displayed when taking a reading and (c)
Whenever the daily reading using the Calibration Standard (S) fails to read 1.9, 2.0 or 2.1.
Refer to Calibration Procedure, Table 2, page 10
1. If the sample volume to be measured is between 2.0 mL and 4.0 mL, insert the Low Volume
Sample Adapter provided prior to calibration. If the volume is greater than 4.0 mL, the Low
Volume Sample Adapter is not needed.
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Nephelometer
™
Italiano: pagine 6 – 8
Español: páginas 8 – 9
8 CFU/mL. Other standards have been used for den-
2 and latex particle suspensions.
Instrument Ambient
Operating Conditions .................... 20 to 30°C
Storage Temperature Range
(Instrument and calibration tube) .. 20 to 30°C
Sample Tube Size ..........................16 – 17 mm dia.,
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flat bottomed glass
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