Primary Name Factor II Assay
Synonym Prothrombin Assay
Synonym Factor II Functional Assay
UAB Procedure Number 2500470
CPT Code 85210
Specimen Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill.

Specimen Management Note time of collection and time of last treatment if applicable. Centrifuge blue-stopper tube within 1 hour of collection, separate plasma and test or quick-freeze at -70°C.
Specimen Accepted Daily including weekends
Test Performed Monday-Friday.
Available Stat? Pathologist's approval required.
Description Congenital factor II (prothrombin) deficiency is caused by one of several rare mutations that reduce prothrombin production or activity. Acquired prothrombin deficiency is caused by vitamin K deficiency, the use of Coumadin therapy, or prothrombin-neutralizing lupus anticoagulant.
Reference Interval 50-150%
Critical Value None
Follow-up Test If the functional prothrombin assay indicates a deficiency, the prothrombin antigen assay may be used to distinguish qualitative from quantitative disorders.
Associated With Bleeding disorders
Associated With Lupus anticoagulant
Associated With Vitamin K deficiency
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