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APTT Inhibitor
MessagePerforming Lab: Regions
Test Code
3532
Alias/See Also
Sunquest: PTTIS; Factor 8/Factor VIII Inhibitor Screen
CPT Codes
85335
Preferred Specimen
Four 3.2% Sodium Citrate Plasma (light blue-top) tubes filled to fill line of 2.7 mL per 3 mL tube
Minimum Volume
1.0 mL plasma aliquot per test
Other Acceptable Specimens
1.0 mL platelet poor plasma (frozen)
Instructions
Processing: Freeze an aliquot of platelet poor plasma at -20C if not performed within 4 hours of collection
Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcl). Freeze immediately and ship on dry ice.
Centrifuge light blue-top tube for 15 minutes at approximately 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcl). Freeze immediately and ship on dry ice.
Transport Container
Transport processed samples frozen on Dry Ice
Transport Temperature
Frozen if > 4 hours old
Specimen Stability
Room Temperature: 4 hours Refrigerated: 4 hours Frozen: 72 hours at -20C or 2 weeks at -80C
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Refrigerated or Room temperature >4 hours.
Hemolyzed or Clotted Samples, Samples do not meet the minimum draw requirements, Samples exceed maximum draw requirements, Samples with hematocrit >55% not collected with the special tube.
Testing must not be performed on patients receiving direct Xa inhibitors (Rivaroxiban, Xeralto, Apixaban) and/or thrombin inhibitor (Dabigatran, Pradaxa, argatroban, hirudin, lepirudin) therapy
Hemolyzed or Clotted Samples, Samples do not meet the minimum draw requirements, Samples exceed maximum draw requirements, Samples with hematocrit >55% not collected with the special tube.
Testing must not be performed on patients receiving direct Xa inhibitors (Rivaroxiban, Xeralto, Apixaban) and/or thrombin inhibitor (Dabigatran, Pradaxa, argatroban, hirudin, lepirudin) therapy
Methodology
Clot Based
Setup Schedule
Monday, Wednesday, Friday
Report Available
3 business days
Reference Range
No evidence of an APTT Inhibitor in this study
Clinical Significance
An inhibitor work-up may be performed on patients who have prolonged APTT’s (not due to anticoagulant therapy). With patients who have a factor deficiency, the addition of normal plasma to patient plasma should correct the APTT into the normal reference range.
