Roche CoaguChek XS Plus, Training Manual

Page: 75 / 78

CoaguChek Professional Monitoring Systems
Training Manual
75
The CoaguChek
®
XS system
Providing patients and their physicians
with quality, reliable results
Calibrated to WHO guidelines for reliability
CoaguChek XS PT test strips are manufactured with a human recombinant tissue factor and have been
assigned an ISI of 1.0
15
according to the WHO guidelines for thromboplastins and plasmas used to
control anticoagulant therapy.
4
The validity of the CoaguChek XS calibration concept has been demon-
strated
16
and is explained in Figure 4.
Excellent performance: high correlation, high accuracy and high precision
The performance of the CoaguChek XS system has been verified in a study conducted at four study
centres, using venous and capillary blood samples on two CoaguChek XS PT Test Strip lots.
13
Labora-
tory testing was performed on frozen plasma samples with six commercial thromboplastins. Results
were assessed using a refined data set of 260 subjects according to the International Organization for
Standardization (ISO) 17593:2007 standard.
14
• High correlation. For patient samples in the therapeutic range (INR 2.0 – 4.5), each of the two test
strip lots met the ISO acceptance limits of ± 0.3 INR (bias –0.19 to 0.18 INR)
• High accuracy. For patient samples with an INR ≤4.5, more than 97 % of all INR differences to a refer-
ence thromboplastin were found within the combined ISO acceptance limits of ± 0.5 INR or ± 30 %
• High precision. For patient samples with an INR ≤4.5, the CV for INR imprecision ranged from 2.0 %
to 3.2 % in venous blood testing, and from 2.9 % to 4.0 % in capillary blood testing (all upper confi-
dence limits of the CVs were <4.5 %)
In another study, a 4-year examination of External Quality Assessment (EQA) for INR tests using
CoaguChek XS and CoaguChek XS Plus systems indicated that the quality of results as indicated by
inter-site variability is similar among POC sites as for hospital laboratories.
10
Fig. 4: (a). A master lot of test strips is directly calibrated by comparison with international reference preparations (IRP) and
represents the manufacturer’s working standard. (b). Further calibration in routine manufacturing of test strips is performed versus
this master lot using whole blood samples from patients on oral anticoagulation and from normal donors.
18
INR: International
Normalized Ratio; IPTcorr: instrument PT (clotting time measured by the system corrected for hematocrit)
INR Calibration according to WHO reference method INR Calibration of the production lots
Blood sample Blood sample
Algorithm Lot specific information
Code Chip
CoaguChek XS
Master Lot
CoaguChek XS
Production Lot
IPT
corr
(sec) IPT
corr
(sec)
IRP manual tilt tube* CoaguChek XS
Master Lot
INR INR
(a) (b)
*For details of the manual tilt tube method, see Poller
10 1/20/2015 8:50:00 AM
Equivalent performance across all CoaguChek XS systems
Equivalence has been demonstrated between INR results determined using the CoaguChek XS system
and INR results determined using the CoaguChek XS Plus system.
19
For three test strip lots, the maxi-
mum mean bias between the CoaguChek XS system and the CoaguChek XS Plus was 0.03 INR for
samples below an INR of 2.0, and 0.07 INR for samples in the therapeutic range of oral anticoagulation
therapy (INR 2.0 – 4.5).
19
The equivalence of the CoaguChek XS Pro and CoaguChek XS Plus systems has also been demon-
strated over the whole hematocrit range, meeting the acceptance criteria for all blood samples.
20
Additional quality features
The CoaguChek XS system also has the following additional features to ensure outstanding quality:
• Integrated Quality Control system. A separate chemical pathway detects deterioration of the strip
chemistry due to exposure to humidity, heat, or light.
18
As a result, no liquid quality control is need-
ed in a CLIA-waived environment
• Hematocrit correction. INR results are corrected for hematocrit within the range of 25 – 55 %, allowing
a broad range of patients to be measured with one device
18
• Hemolysis insensitivity. INR results are insensitive to hemolysis up to 1,000 mg/dL
21
• Heparin insensitivity. Test strips include an anti-heparin agent that has been added to neutralise the
effects of heparin found in blood samples applied to the test strip. INR results are unaffected by
unfractionated heparin up to 1 U/mL and LMW heparin up to 2 U/mL
18
In summary, the CoaguChek XS system from Roche provides patients and their physi­
cians with accurate and precise INR testing through careful calibration to international
standards, ensuring quality, reliable results every time.
11 1/20/2015 8:50:06 AM
18
18
19
17
17
17
20