Optical Aggregometer, easy to use with rapid results, provision for optical aggregation studies, with the facility to upgrade the two channel into a four channel version.

MEASURING PRINCIPLE

Optical method:

The Born type aggregometer or optical aggregometer is a fixed wavelength spectrophotometer with a sample chamber (or chambers) heated to 37C. Provision is made for stirring of the sample because platelet to platelet contact is necessary to the determination of in vitro platelet aggregation. A beam of infra red light shines through two cuvettes, one containing PRP (the sample) and one containing PPP (the reference). The difference in light transmission outputs from the photodiodes is transferred to recording devices. The optical aggregation output is proportional to the continuously measured difference in light transmission between the test and reference samples. When a stimulus is added to the cuvette containing PRP and the platelets respond, changes in light transmission occur and are recorded over time.

PRP, which is turbid, is stirred in a test cuvette maintained at 37C. The light transmittance through this turbid sample is measured relative to the PPP blank. When the agonist is added, the platelets will form increasingly larger aggregates and the PRP will begin to clear, allowing more light to pass through. This increase in light transmittance is directly proportional to the amount of aggregation and is amplified and recorded as a signal on chart paper or digitized into a computer using the software.

MAJOR MERITS

1.The system is FDA cleared and suitable for platelet aggregation studies in PRP, gel-filtered or washed platelets with over-range detection to prevent operation, if a base line is not settable.

2. The system module is supplied complete with AGGRO/LINK 8 interface software package for AGGRO/LINK Opti 4 for aggregation and vW cofactor Opti 4 for Ristocetin CoFactor testing as a complete system.

3. Allows tests to be performed with sample volume 500 µl standard or down to 250 µl with spacers reducing the blood draw volume, rendering it suitable for paediatric and geriatric samples equally well.

4. Very economical with cost per test reduced by almost 50%., while using the high quality, optimised and concentrated Chrono-Par range of reagents and kit for Ristocetin CoFactor assay.

5. Improved reliability with enhanced performance with the self calibration of optical circuit offering a greater level of user convenience.

6. Incorporates two-line LCD display for easy operator guidance with display for temperature, stirrer speed, PRP/reference selection, calibration mode and warning messages for error-free operation.

7. The heater block is under electronic control and selectable between 35°C and 39°C in steps of 0.1°C for excellent temperature control and does not allow operation if exceeding ± 0.2°C from the set temperature.

8. The stirrer speed is adjustable between 400 and 1200 RPM in steps of 100 RPM and an accuracy of 0.01 %, with a stirrer, stopped position for easy adaptation to specific protocols and does not permit operation if the deviation is more than ± 10 RPM from selected speed.

9. Provides for planned expansion with a growing need while protecting investment, with the capability to expand the two channel system into a complete four-channel aggregometer infield, with simple interconnecting cable.

10. The system is well suited for clinical applications including diagnostic studies, detection of von Willebrand disease, monitor the effect of antiplatelet therapy, detect heparin-induced thrombocytopenia and ideal for platelet research, pharmaceutical research and leukocyte aggregation studies.

TECHNICAL DATA

Test Channels : (2) or (4) Channels (Two, 2-Channel Modules,) with : Optical Aggregation – aggregation in PRP, gel-filtered or washed platelet samples.

Front Panel display and controls:

LCD Display – 24 characters x 2-line Liquid Crystal Display, one per channel, displays: * Heater Block – temperature in °C, * luminescence gain, * stirring speed in RPM, * operating mode (Impedance or Optical) * warning messages.

Power ON/OFF switch.

Set Baseline pushbutton(s) – Sets aggregation baseline to 0%.

Mode Switch –Set optical mode

PPP Selector Switch – Set to 1, tests referred to Channel 1 PPP. Set to own channel (2,3,4) test referred to PPP for that channel.

Calibration switch – Key-activated calibration of optical circuits.

Heater Block –set between 35.0°C and 39.0°C in 0.1°C steps. Error detection prevents operation when outside + 0.2°C.

Stirrer – 400 to 1200 RPM in 100-RPM steps with “Stirrer Stopped” position. Error detection prevents operation if not within ± 10 RPM.

Sample volumes:

Optical Aggregation – typically 500 µL PRP; 250 µL with spacers.

General specifications (each module):

Power requirements – Switch selectable 115 or 230 VAC (± 10%), 50/60 Hz, 150 watts max.

Dimensions – 14” (36cm) wide, 8.5” (22 cm) high, 18”(46 cm) deep, Weight – 40 lbs (18 kg)

Incubation wells: Six (6) wells each channel @ 36.5°C ± 1.0°C when temperature set at 37°C.

Output options:

Computer interface – Digital Outputs – RS-232 and USB with AGGRO/LINK 8 software.

Comprehensive diagnostic capability with

Optical (Turbidometric based) aggregometry:

Screen for von Willebrand disease, platelet aggregation tests in PRP or washed platelets. Testing platelet function in PRP for clinical screening +, diagnostic studies, pharmaceutical research and platelet research ++ studies.

+ Clinical– Detect Heparin-Induced Thrombocytopenia, Screen for aspirin like defect, Differentiate between hereditary and acquired platelet disorders, Monitor therapeutic dosage and patient compliance to inhibitory therapy.

++ Research– Study the effects of drugs on platelet aggregation, Study the effects of food substances on platelet function, Study platelet to membrane receptor site defects.

Aggregometer specifications

Two channel Platelet aggregometer with upgradability into four channel, and capable of measuring in PRP by turbidimetry , the classic Born method and shall have FDA cleared and or with CE marking. For 230V 50Hz operation.

Technical:

Test channels:

1. Optical aggregation – Aggregation in PRP, gel filtered or washed platelets with minimum sample volume.

2. Sample volume : Standard : 450µl ; minimum : 250 µl

3. Should be capable of giving reliable results with minimum platelet count difference of 50×10 9 /L.

4. The optics shall be based on dual beam infra-red light sources and photodiode detectors for reliable results.

Display and controls:

Should have clear LCD display, one per channel for display of : (a) Heater block temperature in°C (b) Stirring speed in RPM (c) Operating mode, Born’s method. (d) Warning messages.

Should have key-activated calibration of optical circuits.

Adjustable stirrer speed between 400 to 1200 RPM in 100-RPM steps with “stirrer stopped” position, and error detection to prevent operation, if not within  10 RPM.

PC and software:

(a) Data reduction system: Computer, appropriate to run system software with CD-Writer for convenient storage and retrieval of data , colour monitor and colour inkjet printer should be included. Software package (Windows XP, or the applicable one) should be included.

(b) Should include internal computer interface and software for measuring upto at least two (2) samples for simultaneous aggregation, for a total of two (2) tracings.

(c) Shall have provision for :

(i) Real time display of two channels of amplitude of aggregation.

(ii) Storage facility for reagent data for tracking test value, demography details, for later recall should be available.

(iii)Running with computation of slope log time and area under the curve.

(d) vW cofactor:

(i) On-screen guidance for operator for running the test and incorporate facility for calculation of percent of vW activity and reporting.

(ii) Should allow rerun or deletion of serial point with facility to store curves with lot number, best-fit standard curve and CD calculated for upto six points, should be available.