Inhibitor Anticoagulant Screen
Inhibitor Screen, Circulating Anticoagulant Screen, Mixing Study, Inhibitor/Anticoagulant Screen, Antrim #26513, EPIC: LAB5194, SOFT: INACS
- Specimens collected at Farmington Hills will be performed at Royal Oak Coagulation Laboratory.
- Specimens with hematocrit values greater than 55% must have anticoagulant adjusted. Specimens must be re-collected using a specified whole blood to sodium citrate ratio. Contact the performing Laboratory for specific instructions.
- This test will not be performed on patients receiving heparin, coumadin, LMWH, or direct thrombin inhibitors.
Specimen Collection Criteria
Collect: Three Light Blue-top Becton-Dickinson 3.2% Sodium Citrate tubes.
TUBES MUST BE FULL.
Physician Office/Drawsite Specimen Preparation
For optimal results, maintain whole blood specimen at room temperature (20-26°C or 68-78.8°F) prior to transport. Transport whole blood to the Laboratory within 4 hours of collection. If transport within 4 hours is not possible, the following procedure must be followed for accurate results:
- Centrifuge the capped tube at 1500 x g for 15 minutes.
- Transfer plasma with a plastic pipette into a plastic polypropylene centrifuge tube, cap and centrifuge an additional 15 minutes at 1500 x g to obtain platelet poor plasma (PPP) which has a platelet count less than 10 bil/L. Plasma with a platelet count of less than 10 bil/L is critical for accurate results.
- Immediately remove only the top two-thirds of the PPP and transfer it into two plastic tube.
- Freeze (-20°C/-4°F or below) the PPP specimens immediately.
- Transport frozen on DRY ICE. Specimen must remain frozen during transport.
Preparation for Courier Transport
Transport: Whole blood at room temperature (20-25°C or 68-77°F), or plasma obtained through the process listed above, frozen (-20°C/-4°F or below).
- Glass tubes and 3.8% Sodium Citrate tubes.
- Specimens that are clotted or grossly hemolyzed.
- Inappropriate specimen volume.
- Thawed or partially thawed specimens.
- Specimens collected from patients receiving heparin, coumadin, LMWH, or direct thrombin inhibitors.
Specimen Stability for Testing:
Room Temperature (20-26°C or 68-78.8°F): 4 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable
Platelet Poor Plasma (PPP)
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): 30 days
Specimen Storage in Department Prior to Disposal:
Refrigerated (2-8°C or 36-46°F): 7 days
Farmington Hills specimens sent to Royal Oak Coagulation Laboratory.
Royal Oak Coagulation Laboratory.
Troy Hematology/Coagulation Laboratory.
Sunday - Saturday, 24 hours a day.
Results available within 4 hours of receipt in the Laboratory. If interpretation is required, results available within 72 hours.
No Inhibitor detected.
Light Scatter (Sysmex CA Series).
- Prolonged PT and/or PTT which corrects upon mixing 1:1 with normal pooled plasma indicates factor deficiency. PT and/or PTT which does not correct upon mixing 1:1 with normal pooled plasma indicates inhibitor.
- Immediate inhibitors (those which remain prolonged immediately after mixing 1:1 with normal plasma) are most often lupus-like inhibitors. All inhibitor screens that are positive for immediate inhibitor affecting the aPTT will automatically have a Platelet Neutralization Procedure (PNP) performed to prove phospholipid dependence if enough sample is available.
- Progressive inhibitors (those which prolong further after incubation at 37°C) are most often specific factor inhibitors, such as Factor VIII inhibitors.
- NOTE: The International Society on Thrombosis and Hemostasis (ISTH) recommends that at least two different lupus anticoagulant sensitive tests be normal before excluding the presence of a lupus anticoagulant. Furthermore, if one of these tests is positive, it should be repeated in twelve weeks to exclude a transient, clinically insignificant antibody. Diagnosis of antiphospholipid syndrome (ISTH criteria) requires laboratory evidence of an antiphospholipid antibody (anticardiolipin or beta-2 glycoprotein I of sufficient titer, or lupus anticoagulant) on two occasions at least twelve weeks apart.
This test can assist in the investigation of prolonged PT and/or PTT by the detection/differentiation of inhibitors vs. factor deficiencies. It can further aid in the differentiation of immediate (lupus-like) inhibitors from specific factor inhibitors.
85730x3, 85610x3. If needed: 85670, 85597, 85390
Antrim #26513, EPIC: LAB5194, SOFT: INACS
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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills,
Grosse Pointe, Royal Oak, and Troy campuses.