Inherited Thrombophilias of Pregnancy Profile

CPT: 81240; 85300; 85303; 85306; 85307
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Test Details

Test Includes

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.

Inherited Thrombophilia

VTE Risk per Pregnancy

(No history)

VTE Risk per Pregnancy

(Previous VTE)

Factor V Leiden heterozygote



Factor V Leiden homozygote



Prothrombin gene heterozygote



Prothrombin gene homozygote



Factor V Leiden/prothrombin



Double heterozygote

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.

Specimen Requirements


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

Minimum Volume

1 mL frozen plasma and 3 mL whole blood or two buccal swabs


Blue-top (sodium citrate) tube, lavender-top (EDTA) tube, yellow-top (ACD) tube, or LabCorp buccal swab kit

Patient Preparation

Do not draw from an arm with a heparin lock or heparinized catheter.


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.

Storage Instructions

Freeze plasma. Maintain whole blood and buccal swab kit at room temperature or refrigerate.

Clinical Information


1. Adcock DM, Kressin DC, Marlar RA. Effect of 3.2% vs 3.8% sodium citrate concentration on routine coagulation testing. Am J Clin Pathol. 1997 Jan; 107(1):105-110. 8980376
2. Reneke J, Etzell J, Leslie S, Mg VL, Gottfried EL. Prolonged prothrombin time and activated partial thromboplastin time due to underfilled specimen tubes with 109 mmol/L (3.2%) citrate anticoagulant. Am J Clin Pathol. 1998 Jun; 109(6):754-757. 9620035
3. National Committee for Clinical Laboratory Standardization. Collection, Transport, and Processing of Blood Specimens for Coagulation Testing and General Performance of Coagulation Assays; Approved Guideline. 5th ed. Villanova, Pa: NCCLS; 2008. Document H21-A5:28(5).
4. Gottfried EL, Adachi MM. Prothrombin time and activated partial thromboplastin time can be performed on the first tube. Am J Clin Pathol. 1997 Jun; 107(6):681-683. 9169665
5. McGlasson DL, More L, Best HA, Norris WL, Doe RH, Ray H. Drawing specimens for coagulation testing: Is a second tube necessary? Clin Lab Sci. 1999 May-Jun; 12(3):137-139. 10539100
6. Practice bulletin no 124: Inherited thrombophilias in pregnancy. Obstet Gynecol. 2010 Jul; 116(1):212-222. 20567195


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

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