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Specimen Collection Manual and Test Catalog

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FACTOR II (2) CLOTTING ACTIVITY

Geisinger Epic Procedure Code:  LAB2251    Geisinger Epic ID:  7120

SPECIMEN COLLECTION
Specimen type: 

Platelet-poor plasma


Preferred collection container: 
Alternate collection container: 
Other size blue-top (3.2% sodium citrate) tubes (e.g., 1.8 mL, 4.5 mL)
Specimen required: 

1 mL plasma aliquot for a single factor study. Each additional factor study requires an additional 0.5 mL aliquot. Samples requiring heparin neutralization require an additional 0.5 mL for each factor.


Special notes: 
  • If the patient’s hematocrit (HCT) is >55%, the volume of anticoagulant in the tube must be adjusted. Contact a performing location for sodium citrate adjusted tubes or instruction for how to adjust the sodium citrate.
  • When possible, use fresh venipuncture.
  • Avoid prolong tourniquet time (< 1 minute) and hemolysis during collection as this will alter results.
  • If indwelling catheter or butterfly collection device must be used, draw sample from a non-heparinized lumen or flush the line with 5 mL of saline and discard the first 10 mL of blood.
  • Tubes should be >90% filled.
  • Immediately mix gently after collection by inverting the tube end over end 5 to 6 times. Avoid vigorous mixing or additional inversion. Observe for the presence of clots or hemolysis and recollect if observed.


SPECIMEN PROCESSING
Processing instructions: 

For a single NaCit blue top tube collection create 1 aliquot NaCit and if additional plasma remains, create an additional aliquot NaCit. If multiple tubes are collected, then create 1 aliquot NaCit for each NaCIt blue top tube collected plus one additional aliquot NaCit. Aliquots should be 1.0-1.9 mL and all plasma-based coagulation tests must be moved to aliquot(s).


Transport temperature: 

Frozen on dry ice


Specimen stability: 

Room temperature (whole blood): 4 hours 
Room temperature (plasma off cells): 8 hours 
Frozen (plasma) -20°C: 2 weeks 
Frozen (plasma) -70°C: 6 months 
 


Rejection criteria: 

Clotted, hemolyzed, improperly filled tubes, improper anticoagulant ratio (HCT >55% and citrate not adjusted), refrigerated specimens, or stability exceeded. 

Note: Specimen suspected of thawing in transport, indicated by slant in aliquot or specimen in lid of tube, will have testing performed, and the comment “interpret results with caution as thawing suspected” added to results.



TEST DETAILS
Reference interval: 

83-117%


Additional information: 

Anticoagulation Impact on Coagulation Tests


CPT code(s):  85210
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.
The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.

Test includes: 

Factor II activity


Methodology: 
Mechanical clot-based
Synonyms: 

Factor II, Factor 2, FA2


Clinical significance: 

Factor II or prothrombin is converted to thrombin which is necessary for normal clot formation. It is part of the common clotting cascade, is made in the liver and requires vitamin K for its synthesis. Low levels can result in a bleeding disorder. Factor II levels are decreased in patients with congenital deficiencies (rare), acquired factor II antibodies (rare), vitamin K antagonist (warfarin), vitamin K deficiency from poor oral intake, malabsorption, or improper metabolism (hemorrhagic disease of newborn, cholestasis, certain antibiotic therapy), liver disease, and DIC. Factor II activity assay can be useful in evaluating the reason for both a prolonged PT and aPTT with normal thrombin time.

This assay should not be used to assess the patient’s risk of thrombosis. Please order the Prothrombin Gene Mutation (PGM) if that is the desired test. Pathology will investigate all orders for a Factor II assay to determine correct order practice.


Doctoral Director(s): 
Michelle Grant DO
Review Date:  08/11/2026

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