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Test ID: F_2 Coagulation Factor II Activity Assay, Plasma

Reporting Name

Coag Factor II Assay, P

Useful For

Diagnosing a congenital deficiency (rare) of coagulation factor II


Evaluating acquired deficiencies associated with liver disease or vitamin K deficiency, oral anticoagulant therapy, and antibody-induced deficiencies (eg, in association with lupus-like anticoagulant)


Determining warfarin treatment stabilization in patients with nonspecific inhibitors (ie, lupus anticoagulant)


Determining degree of anticoagulation with warfarin to correlate with level of protein S


Investigation of prolonged prothrombin time or activated partial thromboplastin time

Specimen Type

Plasma Na Cit

Ordering Guidance

Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, we suggest ordering Coagulation Consultations.

Necessary Information

If priority specimen, mark request form, give reason, and request a call-back.

Specimen Required

Specimen Type: Platelet-poor plasma

Patient Preparation: Patient must not be receiving Coumadin or heparin therapy.

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Specimen must be collected prior to factor replacement therapy

2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing

3. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

4. Aliquot plasma into a plastic vial, leaving 0.25 mL in the bottom of centrifuged vial.

5. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, less than or equal to -40° C.

Additional Information:

1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.

2. Each coagulation assay requested should have its own vial.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reference Values

Adults: 75-145%

Normal, full-term newborn infants or healthy premature infants may have decreased levels (≥25%) which may remain below adult levels for ≥180 days postnatal.*

*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing

Day(s) Performed

Monday through Saturday

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
F_2 Coag Factor II Assay, P 3289-6


Result ID Test Result Name Result LOINC Value
F_2 Coag Factor II Assay, P 3289-6

Clinical Information

Factor II (prothrombin) is a vitamin K-dependent serine protease synthesized in liver. It participates in the final common pathway of coagulation, as the substrate for the prothrombinase enzyme complex. Prothrombin is the precursor of thrombin (IIa), which converts fibrinogen to fibrin. Plasma biological half-life is about 3 days.


Deficiency of factor II may cause prolonged prothrombin time and activated partial thromboplastin time. Deficiency may result in a bleeding diathesis.


Liver disease, vitamin K deficiency, or warfarin anticoagulation can cause decreased factor II activity.


Patients that are homozygous generally have levels of less than 25% activity.


Patient that are heterozygous generally have levels of less than 50% activity.


Normal newborn infants may have levels of 25% to 50%.

Clinical Reference

1. Lancellotti S, De Cristofaro R: Congenital prothrombin deficiency. Semin Thromb Hemost. 2009 Jun;35(4):367-381. doi: 10.1055/s-0029-1225759

2. Peyvandi F, Bolton-Maggs PH, Batorova A, De Moerloose P: Rare bleeding disorders. Haemophilia. 2012 Jul;18 Suppl 4:148-153. doi: 10.1111/j.1365-2516.2012.02841.x

3. Girolami A, Scandellari R, Scapin M, Vettore S: Congenital bleeding disorders of the vitamin K-dependent clotting factors. Vitam Horm. 2008;78:281-374. doi: 10.1016/S0083-6729(07)00014-3

4. Brenner B, Kuperman AA, Watzka M, Oldenburg J: Vitamin K-dependent coagulation factors deficiency. Semin Thromb Hemost. 2009 Jun;35(4):439-446. doi: 10.1055/s-0029-1225766

Report Available

1 to 3 days

Method Name

Optical Clot-Based

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