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Test ID F9INH Factor IX Inhibitor Evaluation, Plasma

Useful For

Detection and titering of coagulation inhibitor to the specific factor requested, primarily factor IX in patients with hemophilia B

 

This test is not useful for detecting a nonspecific circulating anticoagulant or the presence of inhibitors directed against other clotting factors.

 

This test is not useful for the detection of lupus anticoagulants.

Method Name

Optical Clot-Based

Reporting Name

Factor IX Inhib Profile

Specimen Type

Plasma Na Cit


Advisory Information


This test is for factor IX inhibitors only. If the presence or type of inhibitor is unknown, either APROL / Prolonged Clot Time Profile, Plasma or ALUPP / Lupus Anticoagulant Profile, Plasma should be ordered first.

 

Multiple coagulation profile tests are available. See Coagulation Profile Comparison in Special Instructions for testing that is performed with each profile.



Shipping Instructions


Send all vials in the same shipping container.



Necessary Information


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

Specimen Required


See Coagulation Guidelines for Specimen Handling and Processing in Special Instructions.

 

Patient Preparation: Fasting preferred

Collection Container/Tube: Light-blue top (3.2% sodium citrate)

Submission Container/Tube: Plastic vials

Specimen Volume: 3 mL in 3 plastic vials each containing 1 mL

Collection Instructions:

1. Specimen must be collected prior to factor replacement therapy.

2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.

3. Aliquot plasma into 3 separate plastic vials (1 mL in each) leaving 0.25 mL in the bottom of centrifuged vial.

4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C, or ideally ≤-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.


Specimen Minimum Volume

2 mL plasma in 2 plastic vials, 1 mL each

Specimen Stability Information

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

Reference Values

FACTOR IX ACTIVITY ASSAY

Adults: 65-140%

Normal, full-term newborn infants or healthy premature infants may have decreased levels (≥20%), which may not reach adult levels for ≥180 days postnatal.*

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

 

FACTOR IX INHIBITOR SCREEN

Negative

 

BETHESDA TITER

0 Units

Day(s) and Time(s) Performed

Monday through Friday; Varies

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

85250-Factor IX activity assay

85335-Bethesda titer (if appropriate)

85335-Factor IX inhibitor screen (if appropriate)

85390-26-Special coagulation interpretation (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
F9INH Factor IX Inhib Profile 3187-2

 

Result ID Test Result Name Result LOINC Value
F_9 Coag Factor IX Assay, P 3187-2

Test Classification

See Individual Test IDs

Profile Information

Test ID Reporting Name Available Separately Always Performed
F_9 Coag Factor IX Assay, P Yes Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IBETH Bethesda Units No No
F9_IS Factor IX Inhib Scrn No No
CCCR Special Coagulation Interpretation No No

Testing Algorithm

Testing begins with coagulation factor IX activity assay with dilutions to evaluate assay inhibition; if the factor IX activity assay is decreased, an inhibitor will be performed to look for specific factor IX inhibition. If specific inhibition is apparent, it will be titered.

NY State Approved

Yes