ITC ProTime Microcoagulation System - Manual (Page 33)

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Accuracy
INR results generated by the ProTime and ProTime3 cuvettes using venous and fingerstick whole blood
samples were compared to INR values obtained using standard laboratory plasma PT methods with samples
collected in 3.2% sodium citrate tubes. The following accuracy data was obtained.
A. Standard ProTime Cuvette vs. Lab (Plasma)
Sample Type Regression Equation r n
Fingerstick Y = 0.94x + 0.38 0.95 229
Venous Y = 0.91x + 0.44 0.94 232
B. ProTime3 Cuvette vs. Lab (Plasma)
Sample Type Regression Equation r n
Fingerstick y = 1.05x + 0.07 0.95 229
Venous y = 0.97x + 0.19 0.95 219
Clinical Performance Comparison
A. ProTime3 vs. ProTime
Linear regression containing clinical fingerstick results from three sites yielded a regression equation
as below:
y = 1.02x - 0.14 r = 0.94 n = 229
B. Patient Self-Testing
In a trial of patient self-testing (PST) in the home vs. professional testing in the clinical and reference
lab, equivalent ProTime results were obtained.
ProTime Professional vs. Patient Self-Testing
y = .94x + 0.13 r = 0.92 n = 421
ProTime Patient Self-Testing vs. Reference Lab
y = .77x + 0.38 r = 0.87 n = 368
Sensitivity
The ProTime instrument is sensitive to deficiencies in vitamin K-dependent coagulation factors known to
influence the PT test (i.e., Factors II, VII and X.)
Hematocrit levels between 20% and 60% do not significantly affect test results.
Quality Control
The ProTime instrument has been designed with multiple systems to ensure proper instrument function.
The instrument self-check at startup checks temperature and timing functions, battery level, and optical,
electrical and mechanical functions. The instrument does not require further calibration. Each ProTime
cuvette has two integral reagent controls that ensure assay reliability and performance. Both levels of
control produce quantifiable clotting endpoints that are compared to pre-set acceptance limits programmed
in the instrument.
Other in-process instrument QC features and the integral reagent controls function together to ensure
correct sample size and collection technique, correct test procedure, instrument functionality and reagent
integrity. A fault message is displayed instead of PT results when any instrument or reagent quality criterion
is not met. When a fault message is displayed, the user should review the product instructions and repeat
the test.