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Test Code Chrom F8 Factor 8 Assay, Chromogenic

Clinical System Name

Factor 8 Assay, Chromogenic


Chromogenic Factor 8
Factor 8, Chromogenic
Factor VIII Chromogenic
Refacto Assay (Recombinant F8)

Sample Requirements

Specimen: Whole Blood

Container(s): Lt. Blue/Citrate

Preferred Vol:  (3) 1.8 mL or (1) 2.7 mL

Minimum Vol:   (2) 1.8 mL



Processing Instructions

Reject due to: Clotted, Hemolyzed, Insufficient quantity, and  Improper collection.

Spin: N

Aliquot: N

Temp: RT

Storage location: Core 6 Freezer  ( -70 C) Send Out rack.


Note:  Deliver blood to Core Coag bench.  Coag Technologist will process. Specimen should be centrifuged within  1 hour of collection. Spin whole blood, remove plasma. Transfer upper 3/4 layer of plasma to plastic tube and make 2 aliquots  0.6 mL, affix large label and store in -70 freezer, Send Out rack.


Off-site collection: Preferred method of collection is venipuncture with vacuum fill. Test results are affected by incorrect blood volumel. Use of a Vascular Access Device for the collection of coag testing is not recommended. If this method is used it requires a 5 cc clearing volume; 3 cc for size 2 French catheter or smaller. Blood must be trasferred to the Lt Blue/Citrate tube by use of the blood transfer device.

Specimen should be centrifuged within 1 hour of collection. Double spin, transfer upper 3/4 layer of plasma to plastic tube affixed with large computer label. Freeze 2 aliquots of 0.6 mL plasma in plastic tubes at -70C.

Ship frozen on dry ice.


Specimen Type Temperature Time
Citrated platelet-poor plasma Room temp N
  Refrigerated N
  Frozen Y



STAT Performed TAT
N  Drawn daily; Performed  M & Th at HMC Coag Lab 5 - 10 d


Performing Laboratory

University of Washington

Dept. of Laboratory Medicine

Harborview Medical Center Coag Lab

1959 NE Pacific St, NW220
Seattle, WA 98195


Phone Number: (206) 520-4600


Department:  Send Outs


Phone Number: (206) 987-2563


CPT Codes




Method: Optical

Analytical Volume: 1.0 mL citrate plasma


Reference Range

50 - 234 %


Send Out Instructions


Reference Test Name: Chromogenic Factor 8
Reference Test Number: CHRF8
Instructions: Send out M - F with the UW courier.