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Lab Test Dictionary

Factor VIII Activity, Clotting with Reflex to Chromogenic Method (70050)


Photometric Clot Detection; Chromogenic Assay


Factor 8

Specimen Type


Performing Lab

Quest Diagnostics San Juan Capistrano

Epic ID

Other Reference Test

Lab Test Days

Wednesday and Saturday

Standard TAT

1-5 Days

Collection Information

Specimen Required

(one-three) 1.8 mL or (one-two) 2.7 mL mL Blood

Container Type

Light Blue (Sodium Citrate)

Processing Information - Lab Use Only

Transport Temperature


Specimen Stability

Room Temp: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 Year

Rejection Criteria

Hemolysis; Received room temp;Received refrigerated; Received thawed

Test Volume Required

3 mL Platelet-Poor Plasma

Minimum Test Volume

1 mL Platelet-Poor Plasma

Processing Instructions

Platelet Poor Plasma: Centrifuge light blue-top tube 15 minutes at approx. 1500 g within 60 minutes of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial. Plasma must be free of platelets (<10,000/mcl). Freeze immediately and send frozen.

Included Tests

If Factor VIII Activity, Clotting is >20, Factor VIII Activity, Chromogenic will be performed.


Note: Storage of whole blood at refrigerated temperatures prior to processing may lead to cryoprecipitate formation and falsely low Factor VIII. A patient must not be given any recombinant vWF or vWF concentrates prior to testing.

CPT Codes

85240; 85240