Art: 715617-00D Rev. Date: 06/11/08
2
i-STAT ACT CALIBRATION
Currently, the i-STAT
®
Celite
®
ACT and i-STAT
®
Kaolin ACT tests are factory calibrated by mathematically
adjusting the raw i-STAT “clot time” to match the Hemochron
®
Celite tube result. This calibration is
performed by testing cartridges and Hemochron Celite tubes side by side, using a range of heparinized,
non-hemodiluted whole blood samples, and using Hemochron tubes prewarmed to 37ºC.
Customers who are familiar with macro-sample ACT methods like Hemochron and Actalyke™, and who do
not preheat their tubes prior to each test, have found that the bias in results between their previous ACT
method and the i-STAT ACT may require changing familiar clotting time target values. In order to ease the
changeover to the i-STAT ACT method under these circumstances, i-STAT now provides a choice between
the current 37ºC result calibration and a new “non-prewarm” (or ambient temperature) result calibration.
The additional calibration mode allows an i-STAT ACT cartridge to deliver results that will be a closer
match for those users who are familiar with macro-sample methods without automatic prewarming cycles,
and should reduce the need to make large changes to ACT target times or ranges. Since micro-sample
methods (Medtronic HR-ACT, Hemochron Jr. ACT+) already incorporate preheating of the test cuvettes,
users with ACT target times and ranges based on these methods should continue to use their current i-STAT
37ºC calibration.