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Order Code LABCHFCX Coagulation Factor X Chromogenic Activity Assay, Plasma

Important Note

Clinic/212

Remember to double spin the specimen and then aliquot it into 2 tubes (divide the plasma equally into each tube).  Freeze both these tubes and band them together when sending to us.

 

 Lab Assistants

When receipt verifying these specimens into the lab, place both aliquot tubes in the freezer and notify the tech that they are there.  Do not thaw the specimen!

 

Techs

After controls are run and acceptable, thaw the barcoded sample in the plasma thawer for 5 minutes. Leave the other tube in the freezer.

Place the sample in a cup, and run.  If unable to obtain a result after 2 runs, order LABGOR FXCH and send specimen to Mayo.

Notify the ordering facility that you are sending the testing to Mayo.

Additional Codes

Test Name in EPIC

EPIC Test Code           

Mnemonic

RV FACTOR X CHROMOGENIC ACTIVITY ASSAY

LABCHFCX

//FXCH//

PRIOR TO 8/1/21:  FXCH

Useful For

Monitoring warfarin anticoagulant therapy, especially in patients whose plasma contains lupus anticoagulants that interfere with baseline prothrombin/INRs and in patients receiving Argatroban who are being transitioned to warfarin.

Specimen Requirements

Draw a full, light blue-top (sodium citrate) tube. Forward unprocessed whole blood promptly at ambient temperature within 4 hours. If collected offsite, please send 2 aliquots (divide the plasma equally into each tube) of frozen platelet-poor plasma. 

Specimen Stability

Specimen Type Temperature Stability             
Whole Blood- Na Cit Ambient 4 hours
Plasma- Na Cit Frozen (See Instructions Below) 14 days

 

Platelet Poor Plasma Instructions:

1. Centrifuge primary tube within 4 hours of draw

2. Transfer plasma to an aliquot tube

3. Centrifuge the aliquot tube

4. Transfer plasma to two separate aliquot tubes

5. Freeze the two aliquot tubes together

Rejection Criteria

Hemolysis Mild OK: Gross reject
Lipemia Mild OK: Gross reject
Icterus Mild OK: Gross reject

Other rejection criteria:    

1.  Clotted Specimen

2.  Volume below minimum fill line or above maximum fill line

Reference Values

≥ 18 years of age: 59% - 130%

 

Therapeutic Range: 
Chromogenic factor 10 levels of 20 to 40% are approximately equivalent to an INR of 2.0 to 3.0 for patients receiving warfarin. Chromogenic factor 10 levels below 20% indicate an INR greater than 3, and levels above 40% indicate an INR of less than 2.

Day(s) Performed

Batched Monday through Sunday 

Results available within 24 hours.

Performing Laboratory

Ridgeview Medical Center

Methodology

Chromogenic Assay