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Test Code F_11 Coagulation Factor XI Activity Assay, Plasma

Important Note

TML Outreach Instruction:  Perform platelet-poor processing

Additional Codes

Torrance Memorial Laboratories Test Code:  68431722

Reporting Name

Coag Factor XI Assay, P

Useful For

Diagnosing deficiency of coagulation factor XI

 

Investigating prolonged activated partial thromboplastin time

Method Name

Optical Clot-Based

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma Na Cit


Ordering Guidance


Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, consider ordering a Coagulation Consultation.



Necessary Information


If priority specimen, mark request form, give reason, and request a call-back.



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: Patient must not be receiving Coumadin (warfarin) or heparin therapy.

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° C or ideally, at or below -40° 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.


Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Cit Frozen 14 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

Adults: 55-150%

Normal, full-term newborn infants or healthy premature infants may have decreased levels (≥10%), which may not reach adult levels for 180 or more days postnatal.*

*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

CPT Code Information

85270

LOINC Code Information

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
F_11 Coag Factor XI Assay, P 3226-8

Test Classification

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.