ITC ProTime Microcoagulation System - Manual (Page 22)

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PERFORMANCE CHARACTERISTICS
The ProTime instrument has been tested extensively by doctors, nurses and patients. Eighty-four people,
ages 7 to 81, participated in the first home-use trial. The trial was conducted to see how well ProTime
results compare to the lab. Comparisons of this type are described by correlation values and a correlation
value near 1.0 means the comparison is good. The home tests compared to tests run at the clinic using
ProTime with venous samples (421 samples) had a correlation of 0.92. The home test results compared to
a reference laboratory results (368 samples) had a correlation of 0.87. These correlation values mean that
home testing is comparable to lab testing.
Precision
Precision testing was conducted with two levels of standard control plasma substrate preparations (Level I
and Level II).
A. Standard ProTime Cuvette
Control Precision n Mean SD
Within day 17 0.9 0.06
Level I
Day-to-day (5 days) 4/day 1.0 0.08
Within day 19 3.2 0.19
Level II
Day-to-day (5 days) 4/day 3.2 0.12
B. ProTime3 Cuvette
Control Precision n mean SD
Within day 18 0.9 0.07
Level I
Day-to-day (5 days) 4/day 0.9 0.12
Within day 20 4.0 0.19
Level II
Day-to-day (5 days) 4/day 4.2 0.22
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