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Test Code FACTOR 12 Factor 12 Assay

Important Note

Method is affected by hemolysis and by improper specimen collection/processing. Patients on hirudin (Refludan) and argatroban (Novastan) may show prolonged clotting times due to the direct thrombin inhibition. This may cause an under-estimation of the factor concentrations.

Clinical System Name

Factor 12 Assay

Synonyms

Factor 12 Activity
Factor XII Activity

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

 

Note: Preferred method of collection is venipuncture with vacuum fill.  Test results are affected by incorrect blood volume.  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 a  blood transfer device to ensure proper fill. 

Specimen should be centrifuged within 1 hour of collection.

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.

Stability

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

 

Availability

STAT Performed TAT
N Drawn daily, Performed M - F at HMC Coag lab 1 - 3 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

Department:  Send Outs

 

Phone Number: (206) 987-2563

Reference Range

Age % Activity
< 1 month 11 - 150
1 - 3 months 17 - 150
3 - 6 months 25 - 150
6 months - 1 year 39 - 150
> 1 year 30 - 150

 

Methodology

Method: Stago STA Clottable Factor assay

Analytical Volume: 1.0 mL citrate plasma

Limitations:

CPT Codes

85280

 

Send Out Instructions

Reference Test Name: Factor XII Activity
Reference Test Number: F12
Instructions: Send out M - F with the UW courier.