Factor 7 activity-994

Test info

  
Factor 7 activity
  
994
  
LAB994
  
MSO
  
Factor VII activity
Proconvertin
  

Evaluate an isolated prolonged PT and document factor VII deficiency

  

Direct Xa or thrombin inhibitor therapy may cause factitiously low results.

Specimen

  
  • Ideally, the patient should not be on anticoagulant therapy
  • Avoid warfarin (Coumadin®) therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing
  
Sodium citrate (Na cit) plasma
  
  
1.0 mL
  
  • If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted.
  • Do not draw from an arm with a heparin lock or heparinized catheter
  • Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio.
  • 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 unless the sample is collected using a winged (butterfly) collection system.
    • With a winged blood collection set a discard tube should be drawn first to account for the dead space of the tubing and prevent under-filling of the evacuated tube.
  • 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 alternative 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.

 

  
  1. Spin
  2. Transfer 1.0 mL plasma to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as Na cit plasma
  3. Freeze
  

Frozen - 28 days

Freeze/thaw cycles - stable x3

  
  • Gross hemolysis
  • Clotted specimens
  • Specimens that have thawed in transit
  • Improperly labeled specimens

Performance

  
LabCorp Burlington (800599): R-NX
  
Daily
  
4 days
  

Prothrombin Time (PT)-based one-stage clotting time assay. Factor VII- depleted plasma is used as the substrate and the substrate and the clotting time with the patient plasma is compared to the clotting time of normal pooled plasma.

Clinical and Interpretive info

  

51 - 186%

Direct Xa or thrombin inhibitor therapy may cause factitiously low results.

Billing

  
85230
  
Result 3198-9

Tracking

  
05/29/2019
  
05/31/2024
  
04/06/2022