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Inherited Thrombophilias of Pregnancy Profile
Activated protein C reflex FVDNA; antithrombin activity; factor II (prothrombin), DNA analysis; protein C, functional; protein S, free
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.
VTE Risk per Pregnancy
VTE Risk per Pregnancy
Factor V Leiden heterozygote
Factor V Leiden homozygote
Prothrombin gene heterozygote
Prothrombin gene homozygote
Factor V Leiden/prothrombin
Antithrombin III activity <60%
3% to 7%
Protein C activity <50%
0.1% to 0.8%
4% to 17%
Protein S free antigen <55%
See individual test descriptions.
Plasma, frozen and whole blood or buccal swab kit (Buccal swab collection kit contains instructions for the use of a buccal swab.)
2 mL frozen plasma and 7 mL whole blood or LabCorp buccal swab kit
1 mL frozen plasma and 3 mL whole blood or two buccal swabs
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 N° 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.
Freeze plasma. Maintain whole blood and buccal swab kit at room temperature or refrigerate.
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|365500||Inherited Thromb. of Pregnancy||015040||Antithrombin Activity||%||27811-9|
|365500||Inherited Thromb. of Pregnancy||117705||Protein C-Functional||%||27819-2|
|365500||Inherited Thromb. of Pregnancy||117763||Act.Prt.C Resist.||ratio||13590-5|
|365500||Inherited Thromb. of Pregnancy||117871||FVDNA TRACKING||N/A|
|365500||Inherited Thromb. of Pregnancy||164519||Protein S, Free||%||27821-8|
|365500||Inherited Thromb. of Pregnancy||511218||Factor II, DNA Analysis||24476-4|
|Reflex Table for Act.Prt.C Resist.|
|Order Code||Order Name||Result Code||Result Name||UofM||Result LOINC|
|Reflex 1||511260||Factor V Leiden Mutation||511262||Factor V Leiden||21667-1|