Chromogenic Factor VIII (8)

Message
For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

If unable to process and properly store specimens within 4 hours of collection then call CompuNet transportation for a STAT pick-up at (937) 297-8262 option 1.


Test Code
CHRMF8


Alias/See Also
76426;
Factor VIII (8) Chromogenic Assay
Factor VIII (8) Chromogenic Activity


CPT Codes
85240

Preferred Specimen
1 plastic (2.7mL) completely filled 3.2% Sodium Citrate (light blue top) tube


Minimum Volume
2 Frozen Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended)


Instructions
Use standard venipuncture and disposal techniques.

Collect the required quantity of Sodium Citrate (light blue top) tubes.

If unable to process specimens within 4 hours of collection then call CompuNet transportation for a STAT pick-up at (937) 297-8262 option 1.

Sodium Citrate (light blue top) tube(s): Process immediately (stable only 4 hours), following instructions below:

Note: We recommend aliquot tubes to be made of polypropylene plastic as this material is safe to freeze at <-70 degrees C.

1. Centrifuge capped Sodium Citrate (light blue top) tubes at 3000 rpm for 10 minutes, or at speed and time required to consistently produce Platelet Poor Plasma (<5/kmm3).

2. Carefully remove the plasma from all Sodium Citrate (light blue top) tubes; avoid disturbing the WBC/buffy coat, and combine all plasma into a 15mL plastic conical centrifuge tube. Note: If the plasma shows any hemolysis, it must be recollected.

3. Centrifuge the plasma in the 10 mL plastic conical centrifuge tube for a second time as in step 1.

4. In one smooth motion, carefully and quickly pour the centrifuged plasma into a second 10 mL plastic conical centrifuge tube. A small amount of plasma along with a red cell button should remain on the bottom of the original conical tube if the pour was executed correctly. Note: This quick-pour method prevents platelet transfer and contamination.

5. Aliquot at least 1mL of plasma into each aliquot tubes labeled “plasma.” Refer to the Minimum Volume section above for the number of aliquots required per test.

6. Finally, place all aliquots into a <-20°C freezer within 4 hours.
Note: Aliquots must remain frozen until they are picked up by the CompuNet courier. Call CompuNet transportation department if frozen specimen boxes are needed.


Transport Container
Whole blood Sodium Citrate (light blue top) tube 
     OR 
Frozen -Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended)


Transport Temperature
Room Temperature: Whole blood Sodium Citrate (light blue top) tube

Refrigerated: Unacceptable for Sodium Citrate (light blue top) tube whole blood or capped plasma aliquots

Frozen: Capped aliquots of Sodium Citr


Specimen Stability
Room Temperature: Whole blood Sodium Citrate (light blue top) tube < 4 hours

Refrigerated: Unacceptable for Sodium Citrate (light blue top) tube whole blood or capped plasma aliquots

Frozen: Capped aliquots of Sodium Citrate plasma (Polypropylene tubes recommended) <7 days at ≤-20 degrees C or
                                                                                                                                             < 6 months at <-70 degrees C


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Rejected for hemolysis, clotted, improper fill, incorrect specimen type, thawed frozen aliquots, refrigerated plasma or blood, expired test tubes, >4 hours old if not processed into separated frozen plasma vials.


Methodology
Chromogenic

Setup Schedule
Monday - Friday
SCOAG


Report Available
1 - 3


Limitations
Heparin level >1.0 IU/mL


Clinical Significance
A chromogenic method of determining Factor VIII activity in human plasma to identify Factor VIII deficiency, for monitoring patients on replacement therapy as well as estimation of Factor VIII activity in concentrates without the influence of Lupus Anticoagulants and non-specific inhibitors.

Method required to monitor Factor VIII activity following HEMLIBRA [Emicizumab-kxwh] infusion.

This assay is especially useful in determining Factor VIII activity on samples drawn from indwelling lines and ports as Heparin levels up to 1.0 IU/mL do not interfere with this methodology.


Performing Laboratory
CompuNet Clinical Laboratories, LLC
2308 Sandridge Drive
Moraine, Ohio 45439


Last Updated: November 19, 2021


The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.