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Coagulation Factor XI Activity Assay, Plasma

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Updated Test Information:

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

Factor 11, UOW1218
Test ID
F11
General Information

Factor XI (11) activity is a PTT-based factor assay used for diagnosing deficiency of coagulation factor XI. A relatively high incidence of congenital factor XI deficiency (Hemophilia C) occurs among individuals of Ashkenazi Jewish descent.


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 WITHIN 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

Clinical assay interference and 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.
Department (code)

Coagulation (COAG)
Methodology

Stago STA Clottable Factor assay
Estimated TAT

By end of next business day
Testing Schedule

Monday - Friday
CPT Code(s)

85270
Reference Range

                                                            Units: %


            Female                                                              Male
Age                   Range                                 Age                   Range
0-29d            23-150                             0-29d                 23-150
1m-2m          27-150                          1m-2m                 27-150
3m-5m          41-150                          3m-5m                 41-150
6m-11m       38-150                        6m-11m                38-150
1y-                   50-150                         1y-                            50-150
STAT Orderable (Y/N)

Yes
Performing Lab

UW
LOINC Code(s)
Collection File View/Download File