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Test Code EMICZ Emicizumab, Modified One Stage Assay Factor VIII, Plasma


Ordering Guidance


For monitoring factor VIII infusions or diagnosing hemophilia, order F8A / Coagulation Factor VIII Activity Assay, Plasma.



Necessary Information


 



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation: For at least 12 hours before specimen collection, the patient should not be given infusions of factor VIII concentrates.

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

Submission Container/Tube: 13-mm x 75-mm, 5-mL, plastic vial (polypropylene preferred)

Specimen Volume: 1 mL Platelet-poor plasma

Collection Instructions:

1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing

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

3. Aliquot plasma into a plastic vial, leaving 0.25 mL in the bottom of centrifuged vial.

4. Immediately freeze plasma (no longer than 4 hours after collection) at -20° C or, ideally, at -40° C or below.

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.


Useful For

Monitoring compliance or potential development of an antidrug antibody

 

This assay is not indicated for monitoring factor VIII infusions or for making a diagnosis of hemophilia.

Disease States

  • Hemophilia A

Reporting Name

Emicizumab, modified OSA FVIII, P

Specimen Type

Plasma Na Cit

Specimen Minimum Volume

Platelet-poor plasma: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma Na Cit Frozen 42 days

Reference Values

<1 mcg/mL

Method Description

The emicizumab (Hemlibra) assay is a modification to the one stage factor VIII assay performed on the Instrumentation Laboratory (IL) ACL TOP using the activated partial thromboplastin time (IL SynthASil APTT) method and a factor-deficient substrate. Patient plasma is combined and incubated with a factor VIII-deficient substrate (Precision Biologic, normal plasma depleted of factor VIII 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 and interpolated against a drug specific calibration.(Owen CA Jr, Bowie EJW, Thompson JH Jr. Diagnosis of bleeding disorders. 2nd ed. Little, Brown and Company; 1975; Cielsa B. Defects of plasma clotting factors. In: Hematology in Practice. 3rd ed. FA Davis; 2019:chap 17)

Specimen Retention Time

7 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EMICZ Emicizumab, modified OSA FVIII, P 99614-0

 

Result ID Test Result Name Result LOINC Value
EMICZ Emicizumab, modified OSA FVIII, P 99614-0

Day(s) Performed

Monday through Friday

Report Available

1 to 7 days

Forms

If not ordering electronically, complete, print, and send an Coagulation Test Request (T753) with the specimen.

Reject Due To

  All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.