Calculations; Reporting Results - Chrono-Log 490 4+4 Instruction Manual

b. If calculating Slope, Amplitude, Lag Time and Area
Under the Curve at the same settings:
1) Click on Trace 1
2) Click on "Set All" to calculate all parameters with
one setting.
3) Follow Steps 2) through 4) above.
NOTE – When calculating Lag Time individually, only a start time
is displayed.
19. After setting the Start and Stop Times, Click on DONE, then
select Calculate Results under the EDIT window (or use
ICON). This command will calculate aggregation percentage,
slope and if selected, lag time and area under the curve.
Check Duration times to be sure Start & Stop Lines were set
correctly. Click on OK and calculations will appear in Data
Box.
20. After the calculations have been completed, SAVE the test,
using the SAVE command under FILE. Tests can be printed
using the PRINT command in the FILE WINDOW. PRINT is for
printing one test per page.
21. To print multiple test graphs separately at one time or in a
Report Format, click on File and Report Batch Print, followed
by:
a. Select the tests to be printed by placing (√) in boxes to
left of tests listed.
b. Click on the "Insert Selected" button to move tests to
lower panel.
c. The order the tests are printed out can be arranged by
using UP or DOWN buttons.
d. Click on "Report Print" to include all selected tests in a
single report ... or,
e. Click on "Batch Print" to print each test separately.
22. Remove the samples from the reaction well and discard.

CALCULATIONS:

1. Amplitude – Optical aggregation results are expressed as a
percentage of aggregation at a given time interval from
reagent addition; 100% aggregation is defined as the
difference between the 0% (PRP) baseline and the 100%
(PPP) baseline.
2. Slope – Slope is determined by drawing a tangent through
the steepest part of the curve. A right triangle is then
constructed over an interval of one minute. The height of
the triangle is the rate of change of aggregation in one
minute, which is defined as the slope. AGGRO/LINK®
Opti8 TM
Software can be set from 16 to 99 seconds (32 point to 198
point) sliding curve. To change the length of a slope line,
click on EDIT, then ADJUST SLOPE LINE. Click on Trace
number and use arrows to adjust slope length up to 99
seconds. Chrono-log standard setting is 16 seconds (32
points).

REPORTING RESULTS:

1. Report Hematocrit.
2. Report Platelet Count.
3. Report Platelet Aggregation percent and slope.
Document # 49044IM1
Revision 7.5
Dated February 16, 2017
Reference Ranges:
NOTE: The following Normal Ranges were obtained from
various laboratories and publications. They should be used as a
guideline only. Normal ranges should be established for
aggregation in each and every laboratory.
Normal Ranges in Platelet Rich Plasma
(Mean ± ± ± ± 1 SD)
Reagent Conc.
Collagen 2 µg/mL
Arachidonic Acid 0.5 mM
ADP 10 µM
Epinephrine 5 µM
Ristocetin 1.25mg/mL
+
(* 2 SD)
Procedures for Abnormal Results:
1. When Normal Control Test(s) Is Abnormal
a. No patient result shall be reported if any reagent does
not recover findings within reference range limits
when tested with the normal control.
b. Repeat both Normal Control and Patient test with new
aliquot of frozen reagent or reconstitute new vial of
reagent. Be sure each test cuvette contains a stir bar.
2. When Normal Control Test(s) Is Normal
a. Repeat abnormal patient test(s) to be sure result is not
due to a technical variable. Be sure each test cuvette
contains a stir bar.
b. If repeated test(s) continue to be abnormal, report the
abnormal result(s) and request a retest on another day
to confirm findings.
Platelet Abnormalities
Platelet aggregation is clinically significant in the detection and
diagnosis of acquired 14 or congenital qualitative platelet defects.
The platelet's ability or inability to respond to particular
aggregating reagents is the basis for differentiating platelet
dysfunctions as shown in the table on the following page.
13
18
Agg. (%)
70 – 94
74 – 99* 13
71 – 88
78 – 88
13
87 – 102