Prekallikrein assay

Alphabetical Test listing

Prekallikrein assay-994

Prekallikrein assay
Fletcher factor assay

Measurement of prekallikrein factor concentration


Do not draw from an arm with a heparin lock or heparinized catheter.

Sodium citrate (Na cit) plasma
2.0 mL
1.0 mL

Do not draw from an arm with a heparin lock or heparinized catheter.

  1. Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate
  2. Evacuated collection tubes must be filled to completion to ensure a proper blood to anticoagulant ratio. Coag - Tube fill guidelines
  3. Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times to prevent clotting
  1. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma using a plastic transfer pipette, being careful not to disturb the cells.
  2. Deliver to a plastic transport tube, cap, and recentrifuge for 10 minutes.
  3. Use a second plastic pipette to remove the plasma, staying clear of the platelets at the bottom of the tube.
  4. Transfer the plasma into a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp) , labelled as PPP.
  5. Freeze

Frozen (preferred)

Ambient - 4 hours

LabCorp Burlington (500194): R-NX
8 days

Factor prekallikrein activity is determined utilizing an aPTT-based one-stage clotting time assay. Factor prekallikrein-depleted plasma is used as the substrate, and the clotting time with the patient plasma is compared to the clotting time of normal pooled plasma.


Normal: ≥ 50 %

Result 28659-1