Dianne Kitchen TEG rotem qc

Thrombelastography (TEG) and
Rotational Thromboelastometry (ROTEM):
UK NEQAS for Blood Coagulation pilot scheme
Dianne Kitchen
Specialist scientific lead for POC programmes
UK NEQAS ( Blood Coagulation), Sheffield, UK

N ational
E xternal
Q uality
A ssessment
S cheme
Not for profit organisation
Part of NHS
Role is to improve quality of testing and
ultimately patient care

quality control
the process of looking at goods when they are
being produced to make certain that all the
goods are of the intended standard
In a medical situation
To ensure all results are valid and accurate (and
to be able to prove that the correct procedures
were in place)

Internal QC
Purchased from manufacturer
Compares your result to a pre
determined range
On-going process
Are my results the same
today as they were yesterday
Precision/ Reproducibility
External QA
A service from an external
organisation
Compares your result with
other users
Spot check
Are my results the same as
other centres doing the same
test
Accuracy

If the True result is
the bull's-eye, this
group of tests is
inaccurate and
imprecise

If the True result is
the bull's-eye, this
group of tests is
inaccurate but
precise

If the True is the
bull's-eye, this group
of tests is both
accurate and precise

Tests of global haemostasis
Often used in a POC setting such as theatres
Allow reduction in turnaround time of tests
Often used by non laboratory staff
Quality control not always performed

®
Cup rotates pin is
stationary
Cup are either Plain cup
or Heparinase cup

®
Pin rotates Cup is stationary
Many reagents available,
INTEM, EXTEM and
HEPTEM

Time for clotting to
begin
Time until clot is 20 mm
Rate of clot growth
Clot firmness - trace
width
ROTEM
CT (sec)
CFT (sec)
Angle( degrees)
MCF (mm)
TEG
R (min)
K (min)
Angle (degrees)
MA (mm)

ROTEM / TEG analysis
Angle
time
60 mm
20 mm
maximum clot
firmness
(MCF / MA) [mm]
clotting time (CT / R)
clot formation time (CFT / K)

Introduced in April 2006 as a pilot study
Performed 8 surveys with 2 sample per survey
Samples are lyophilised plasma, provided with
diluent and pipette to reconstitute
Parameters to test are
For TEG
R, K, Angle and MA at 30 minutes
For Rotem- CT, CFT, Angle, A10, A20 and MCF at
30 minutes

Plain cup n=40
Heparinase cup n=40
Median
CV%
Range
Median
CV%
Range
R (mins)
6.3
26.7
5.2-14.1
6.7
25.7
5.3-13.0
Angle
76.2
8.8
54.8-79.8
74.8
10.0
43.2-80.7
K (mins)
0.9
51.9
0.8-3.8
1.0
47.1
0.8-3.6
MA
(mm at 30
mins)
44.6
10.6
39.6-69.0
43.7
6.8
37.6-49.6
This was a normal pooled sample
Interpretations of R time for this sample were 25/33 normal for
Plain cup and 22/31 were normal for heparinase cup

INTEM n=16
EXTEM n=16
Median
CV%
Range
Median
CV%
Range
CT (secs)
149
12.6%
135-196
43.5
131.4%
35-417
Angle
84.5
1.2%
81-85
85
7.0%
62-87
CFT (secs)
28
16.4%
24-43
26
91.4%
19-147
A10 (mm)
35.5
8.0%
30-41
37
7.2%
34-43
A20 (mm)
MCF (mm at
30 mins)
38.3
38.5
6.9%
9.4%
34-43
30-46
This was a normal pooled sample
39.5
41
7.5%
8.2%
Interpretations of CT for this sample were 12/14 normal for
INTEM and 10/11 for EXTEM normal
37-47
38-50

INTEM n=16
EXTEM n=16
Result
Median
Result
Median
CT (secs)
182
149
417
43.5
Angle
81
84.5
62
85
CFT (secs)
43
28
147
26
A10 (mm)
30
35.5
34
37
A20 (mm)
38
38.3
37
39.5
MCF (mm at 30
mins)
30
38.5
38
41
EXTEM results showed some major deviations from to median value
Upon contact reagents for this test were found to be out of date

Plain cup n=35
Heparinase cup n=35
Median
CV%
Range
Median
CV%
Range
R (mins)
18.0
22.8
12.7-25.2
MA (mm at
30 mins)
No clotting achieved
40.8
51.3
3.7-56.5
This was a sample with added heparin to mimic a heparinised patient
Interpretations of R time for this sample were 31/31 abnormal for Plain
cup and 24/24 were abnormal for heparinase cup

INTEM n=15
HEPTEM n=13
Median
CV%
Range
Median
CV%
Range
CT (secs)
MCF (mm at
30 mins)
No clotting achieved
354
60
19.0
3.8
281-
516
56-64
This was a sample with added heparin to mimic a heparinised patient
Interpretations of CT for this sample were 15/15 abnormal for INTEM and
6/7 were abnormal for HEPTEM

Quality control is essential for any test whether
laboratory based or POC.
Participation in an EQA programme can help to
ensure reliable results
EQA performance will give reassurance that the
tests are giving similar results to other users

www.ukneqasbc.org
dianne.kitchen@coageqa.org.uk