Abbott i-STAT 1 System Manual page 490

Factors Affecting Results
• The presence of exogenously added heparin, citrate, oxalate, or EDTA from blood collection devices
will interfere with test results.
• Poor technique in sample collection may compromise the results. (See Specimen Collection and
Preparation below.)
• Glass syringes or tubes may prematurely activate coagulation, resulting in accelerated clotting times
and lower INRs. Venous samples must be collected into plastic syringes or tubes.
• PT/INR results may be affected by commonly administered drugs.
• Abbott Point of Care has not characterized the i-STAT PT/INR test with patients that have lupus
anticoagulant antibodies. If the presence of lupus anticoagulant antibodies is known or suspected,
consider using a prothrombin time laboratory assay using a reagent that is known to be insensitive
to lupus anticoagulant antibodies or an alternate laboratory method.
Limitations of the i-STAT PT/INR Test
• The analyzer must remain on a level, vibration-free surface with the display facing up during testing.
A level surface includes running the handheld in the downloader/recharger.
• The i-STAT PT/INR test is not affected by fibrinogen concentrations between 70 and
541 mg/dL. The i-STAT PT/INR electrogenic test methodology does not measure the physical clot
and is not dependent on whether or not fibrinogen forms into an actual physical fibrin clot. As
such, the i-STAT PT/INR test will not reflect the extension of coagulation time associated with the
depletion of fibrinogen (e.g., consumptive coagulopathy), disseminated intravascular coagulation, or
defibrination syndrome.
• The i-STAT PT/INR test is not affected by unfractionated heparin concentrations up to 1.0 U/mL.
• Hematocrits in the range of 24 – 54% PCV have been demonstrated not to affect results.
• Cubicin (daptomycin for injection) has been found to cause a concentration-dependent false
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prolongation of prothrombin time (PT) and elevation of INR when using the i-STAT PT/INR test. It
is recommended that for patients being treated with this antibiotic, an alternate method be used to
evaluate PT/INR.
• The i-STAT PT/INR test may report a false prolongation of the prothrombin time (PT) and an
elevation of the INR on samples contaminated with chlorhexidine gluconate.
• The i-STAT PT/INR test is not intended for evaluating individual factor deficiencies.
PT/INR - 6
Art: 715236-01M Rev. Date: 01-Jul-13