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Print CPT 81240; 85300; 85303; 85306; 85307
Test Details
Turnaround Time
2 - 10 days
Use
Thrombophilias contribute to a number of pregnancy complications, including fetal loss, placental abruption, and poor fetal growth.6 It has been estimated that thromboembolism complicates approximately one in 1600 births in the US.6 Pregnancy is associated with increased clotting potential, decreased anticoagulant activity, and decreased fibrinolysis. The risk for thrombosis is further exacerbated by venous stasis in the lower extremities due to compression of the inferior vena cava and the pelvic veins by the enlarging uterus, a hormone-mediated increase in venous capacitance, insulin resistance, and hyperlipidemia.6 While there is a strong association between inherited thrombophilias and venous thromboembolism, its role as a cause of adverse pregnancy outcomes, such as fetal loss, preëclampsia, and fetal growth restriction, is not as well defined. A recent American Congress of Obstetricians and Gynecologists (ACOG) practice bulletin made recommendations as to the appropriate use of laboratory tests for inherited thrombophilias of pregnancy.6 This publication also listed the risks of thrombosis associated with a number of inherited thrombophilias, both in pregnant women with and without a history of previous thrombosis.
Inherited Thrombophilia | VTE Risk per Pregnancy (No history) | VTE Risk per Pregnancy (Previous VTE) |
|---|---|---|
Factor V Leiden heterozygote | <0.3% | 10% |
Factor V Leiden homozygote | 1.5% | 17% |
Prothrombin gene heterozygote | <0.5% | >10% |
Prothrombin gene homozygote | 2.8% | >17% |
Factor V Leiden/prothrombin | 4.7% | >20% |
Double heterozygote | ||
Antithrombin III activity <60% | 3% to 7% | 40% |
Protein C activity <50% | 0.1% to 0.8% | 4% to 17% |
Protein S free antigen <55% | 0.1% | 0.22% |
Test Includes
Activated protein C reflex FVDNA; antithrombin activity; factor II (prothrombin), DNA analysis; protein C, functional; protein S, free
Methodology
See individual test descriptions.
Related Documents
For more information, please view the literature below.
Procedures for Hemostasis and Thrombosis: A Clinical Test Compendium
Specimen Requirements
Information on collection, storage, and volume
Specimen
Plasma, frozen, and whole blood or buccal swab kit (Buccal swab collection kit contains instructions for the use of a buccal swab.)
Volume
1 mL frozen plasma and 7 mL whole blood or Labcorp buccal swab kit
Container
Blue-top (sodium citrate) tube, lavender-top (EDTA) tube, yellow-top (ACD) tube, or Labcorp buccal swab kit
Storage Instructions
Freeze plasma. Maintain whole blood and buccal swab kit at room temperature or refrigerate.
Collection
Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate.1 Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.2,3 The sample should be mixed immediately by gentle inversion at least six times to ensure adequate mixing of the anticoagulant with the blood. A discard tube is not required prior to collection of coagulation samples.4,5 When noncitrate tubes are collected for other tests, collect sterile and nonadditive (red-top) tubes prior to citrate (blue-top) tubes. Any tube containing an alternate anticoagulant should be collected after the blue-top tube. Gel-barrier tubes and serum tubes with clot initiators should also be collected after the citrate tubes. Centrifuge blue-top tube for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube. Transfer the plasma into a Labcorp PP transpak frozen purple tube with screw cap (Labcorp No. 49482). Freeze immediately and maintain frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Please print and use the Volume Guide for Coagulation Testing to ensure proper draw volume.