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Coagulation Factor XII Activity Assay, Plasma

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Updated Test Information:

Test Description
Coagulation Factor XII Activity Assay, Plasma
Synonym(s)

Factor 12, UOW1219
Test ID
F12
General Information

Factor XII (12) activity is a PTT-based factor assay and used for diagnosing deficiency of factor XII (12). Factor XII deficiency is often discovered when patients have prolonged PTT but do not exhibit any bleeding diathesis.


Emicizumab (Hemlibra) will affect all PTT-based assays and will overestimate the factor concentrations.
Container Type

3 mL or 5 mL Light Blue Citrate Tube
Specimen Type

Blood
Specimen Requirements

Entire Specimen
Specimen Collection / Processing Instructions

MUST PROCESS WITH 4 HOURS OF COLLECTION
Platelet poor Coag Citrate Specimen processing:
1. Gently invert tube 2-3 times prior to placing in Centrifuge
2. Centrifuge Citrate whole blood at 4500 rpm for 10 minutes
3. Carefully pipette plasma, avoiding the platelet/buffy coat into a plastic vial
4. Centrifuge plasma at 4500 rpm for 10 minutes
5. Pipette the plasma to a plastic vial, leaving the bottom 0.25 mL undisturbed
6. Freeze plasma immediately and transport frozen. 
Minimum Sample Volume

1 mL
Limitations

Patients on bivalirudin (Angiomax), dabigatran (Pradaxa), argatroban (Novastan), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa) may show prolonged clotting times. This may cause an under- estimation of the factor concentrations. Emicizumab (Hemlibra) will affect all PTT-based assays and will overestimate the factor concentrations.


Elevated factor VIII level (>250%) will result in a false increase of factor IX, XI, or XII.
Department (code)

Coagulation (COAG)
Methodology

Stago STA Clottable Factor assay
Estimated TAT

Report by the next business day
Testing Schedule

Monday - Friday
CPT Code(s)

85280
Reference Range

                                          Units: %
Female                                                               Male
Age                 Range                           Age                Range
0-29d           11-150                        0-29d            11-150
1m-2m        17-150                      1m-2m            17-150
3m-5m        25-150                      3m-5m            25-150
6m-11m     39-150                      6m-11m         39-150
1y-                 30-150                      1y-                    30-150
Performing Lab

UW
LOINC Code(s)

3232-6
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