Prothrombin Fragment 1+2

CPT: 83520
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Expected Turnaround Time

3 - 9 days

Related Documents

For more information, please view the literature below.

Procedures for Hemostasis and Thrombosis: A Clinical Test Compendium

Specimen Requirements


Plasma, frozen


2 mL

Minimum Volume

1 mL


Blue-top (sodium citrate) tube


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 and carefully remove the plasma using a plastic transfer pipette, being careful not to disturb the cells. 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.

Storage Instructions

Freeze; three freeze/thaw cycles are acceptable. Stable at room temperature or refrigerated for four hours.

Patient Preparation

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

Test Details


Evaluation of F 1+2 in plasma is a determinant of in vivo thrombin generation.


Traumatic venipuncture or prolonged stasis may invalidate results.6 Improper mixing of the specimen after venipuncture can falsely elevate F 1+2 levels.


F 1+2 is measured by an enzyme immunoassay based on the sandwich principle.6 F 1+2 in the sample binds to anti-F 1+2 antibodies fixed to the microtiter plate during an incubation period. Peroxidase conjugated antibodies are then added and a second incubation takes place. A chromophore is added and color formation is directly proportional to the concentration of F 1+2.

Additional Information

Prothrombin fragment 1+2 (F 1+2) is the amino terminus fragment of the prothrombin molecule. It is a polypeptide with a half-life of approximately 90 minutes.6 F 1+2 is released from prothrombin when prothrombin is converted to thrombin by the prothrombinase complex. The prothrombinase complex consists of activated factors X and V, calcium ions, and phospholipid. F 1+2 has been utilized to assess thrombotic risk and monitor anticoagulant therapy. Increases of F 1+2 occur as a result of increased conversion of prothrombin to thrombin. F 1+2 levels are elevated in patients with deep vein thrombosis, pulmonary embolism, disseminated intravascular coagulation, septicemia, preëclampsia, eclampsia, and trauma. F 1+2 is elevated as much as two times normal in patients with antithrombin deficiency. F 1+2 is decreased below the reference range in patients undergoing oral anticoagulant therapy and levels may be used to assess efficacy of anticoagulant therapy. F 1+2 may be accompanied by increases in other markers of clot formation and lysis such as fibrinopeptide A, thrombin-antithrombin complex, and D-dimer.


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, Ng 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 pPartial 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. Adcock DM, Bethel MA, Macy PA, et al. Coagulation Handbook. Esoterix Coagulation; 2006.


Bauer KA, Rosenberg RD. The pathophysiology of the prethrombotic state in humans: Insights gained from studies using markers of hemostatic system activation. Blood. 1987 Aug; 70(2):343-350. 3607275
Bauer KA, Weitz JI. Laboratory markers of coagulation. In: Coleman RW, Hirsh J, Marder VJ, et al, eds. Hemostasis and Thrombosis Basic Principles & Clinical Practice. 4th ed. Philadelphia, Pa: Lippincott William and Wilkins; 2000:1113-1129.
Conway EM, Bauer KA, Barzegar S, Rosenberg RD. Suppression of hemostatic system activation by oral anticoagulants in the blood of patients with thrombotic diathesis. J Clin Invest. 1987 Dec; 80(6):1535-1544. 3680513


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
500016 Prothrombin Fragment 1+2 MoAb 500789 Prothrombin Fragment 1+2 MoAb pmol/L 27824-2

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