Abbott i-STAT 1

Abbott Point of Care Inc. • Abbott Park, IL 60064 • USA
Art: 716240-00D Rev. Date: 03-Mar-10
Technical BulleTin
i-STAT
®
K
2
EDTA and K
3
EDTA Customization for Hematocrit on the
i-STAT
®
System
PURPOSE
This Technical Bulletin contains the information needed to select the K
2
EDTA or K
3
EDTA customization
option for reporting hematocrit results on the i-STAT System.
HEMATOCRIT CALIBRATION
The reference method for hematocrit is the microhematocrit (MH) method. All instruments measuring
hematocrit are expected to be traceable, or calibrated, to this reference method.
1-3
The microhematocrit reference method described in CLSI H7-A3
3
permits both K
2
EDTA and K
3
EDTA
anticoagulant sample collection tubes. K
3
EDTA anticoagulant shrinks red blood cells relative to K
2
EDTA
anticoagulant, causing microhematocrit results from K
3
EDTA samples (MH-K
3
EDTA) to be lower by
approximately 2 – 4% than results from K
2
EDTA samples (MH-K
2
EDTA).
3,4
Consequently, instruments calibrated to MH-K
3
EDTA report lower hematocrit results than analyzers
calibrated to MH-K
2
EDTA.
SELECTION OF THE K
2
EDTA OR K
3
EDTA CUSTOMIZATION SETTINGS ON THE i-STAT
SYSTEM
i-STAT provides two customization settings for reporting hematocrit results: The “K
3
EDTA” customization
reports hematocrit results traceable to MH-K
3
EDTA. The “K
2
EDTA” customization reports hematocrit results
traceable to MH-K
2
EDTA.
For best agreement of i-STAT and hematology analyzer hematocrit results, the i-STAT customization
setting is selected according to the calibration of the comparative hematology analyzer (MH-K
2
EDTA or
MH-K
3
EDTA).
When this Technical Bulletin was first released, the manufacturers of the Advia
®
, Cell-Dyn
®
, Coulter
®
, and
Sysmex
®
, hematology analyzers used samples collected in K
3
EDTA for the purpose of calibrating their
systems to reference methods. The manufacturers of Advia, Cell-Dyn and Sysmex now use samples
collected in K
2
EDTA for the purpose of calibrating their systems to reference methods. Therefore, for best
agreement between these analyzers and the i-STAT System, the K
2
EDTA customization setting should be
selected. (Note: The default setting on the i-STAT System is K
3
EDTA.)