Diagnosing deficiency of coagulation factor XI
Investigating prolonged activated partial thromboplastin time
Optical Clot-Based
Factor XI Activity Assay
F11
Factor XI
Plasma Na Cit
Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, we suggest ordering Coagulation Consultations.
If priority specimen, mark request form, give reason, and request a call-back.
Patient Preparation: Patient must not be receiving Coumadin or heparin therapy.
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Specimen must be collected prior to factor replacement therapy.
2. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.
3. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.
4. Aliquot plasma into a plastic vial, leaving 0.25 mL in the bottom of centrifuged vial.
5. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or, ideally, less than or equal to -40 degrees C.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.
0.5 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Cit | Frozen | 14 days |
Diagnosing deficiency of coagulation factor XI
Investigating prolonged activated partial thromboplastin time
Factor XI is synthesized in the liver
Factor XI deficiency may cause prolonged partial thromboplastin
Adults: 55-150%
Normal, full-term newborn infants or healthy premature infants may have decreased levels (> or =10%) which may not reach adult levels for > or =180 days postnatal.*
*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.
Acquired deficiency is associated with liver disease and rarely inhibitors.
Patients that are homozygous: <20% activity
Patients that are heterozygous: 20% to 60% activity
Decreased plasma levels of factor XI do not correlate well
1. He R, Chen D, He S: Factor XI: hemostasis, thrombosis, and antithrombosis. Thromb Res. 2012 May;129(5):541-550
2. Martin-Salces M, Jimenez-Yuste V, Alvarez MT, Quintana M, Hernandez-Navarro F: Review: Factor XI deficiency: review and management in pregnant women. Clin Appl Thromb Hemost. 2010;16(2):209-213
3. Seligsohn U: Factor XI in haemostasis and thrombosis: past, present and future. Thromb Haemost. 2007 Jul;98(1):84-89
4. Santoro R, Prejano S, Iannaccaro P: Factor XI deficiency: a description of 34 cases and literature review. Blood Coagul Fibrinolysis. 2011 Jul;22(5):431-435
The factor XI assay is performed on the Instrumentation Laboratory ACL TOP using the activated partial thromboplastin time (APTT) method and a factor-deficient substrate. Patient plasma is combined and incubated with a factor XI-deficient substrate (normal plasma depleted of factor XI by immunoadsorption) and an APTT reagent. After a specified incubation time, calcium is added to trigger the coagulation process in the mixture. Then the time to clot formation is measured optically at a wavelength of 671 nm.(Owen CA Jr, Bowie EJW, Thompson JH Jr: Diagnosis of Bleeding Disorders. 2nd ed. Little, Brown and Company; 1975; Meijer P, Verbruggen HW, Spannagi M: Clotting factors and inhibitors: Assays and interpretation. In: Kottke-Marchant K, ed. Laboratory Hematology Practice. Wiley Blackwell Publishing; 2012:435-446)
Monday through Saturday
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
85270
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
F_11 | Coag Factor XI Assay, P | 3226-8 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
F_11 | Coag Factor XI Assay, P | 3226-8 |