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HelpTest Code F_2 Coagulation Factor II Activity Assay, Plasma
Reporting Name
Coag Factor II Assay, PUseful 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
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Plasma Na CitOrdering 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: Â Patient must not be receiving coumadin (warfarin) or heparin therapy. (If not possible for medical reasons, note on request.)
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, -40° C or below.
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 |
Special Instructions
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
85210
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.
Interpretation
Liver disease, vitamin K deficiency, or warfarin anticoagulation can cause decreased factor II activity.
Normal newborn infants may have levels of 25% to 50%.
Cautions
Factor II is one of the last vitamin K-dependent coagulation factors to decrease after starting warfarin therapy and one of the last to return to normal when anticoagulation is discontinued. It may take 10 to 14 days for a return to baseline levels.
Clinical Reference
1. Lancellotti S, De Cristofaro R. Congenital prothrombin deficiency. Semin Thromb Hemost. 2009;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;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;35(4):439-446. doi:10.1055/s-0029-1225766
5. Favaloro EJ and Lippi G. eds. Hemostasis and Thrombosis, Methods and Protocols. Humana Press 2017
Report Available
1 to 3 daysSpecimen Retention Time
7 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Method Name
Optical Clot-Based
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.
Method Description
The factor II assay is performed on the Instrument Laboratory ACL TOP using the prothrombin time (PT) method and a factor-deficient substrate. Patient plasma is combined and incubated with a factor II-deficient substrate (normal plasma depleted of factor II by immunoadsorption). After a specified incubation time, a PT reagent is added to trigger the coagulation process in the mixture. Then the time to clot formation is measured optically at a wavelength of 671 nm.(Owen CA Jr, Bowie EJW, Thompson JH Jr: Diagnosis of Bleeding Disorders. 2nd ed. Little, Brown and Company; 1975; Meijer P, Verbruggen HW, Spannagi M: Clotting factors and inhibitors: Assays and interpretation. In: Kottke-Marchant K, ed. Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012:435-446)