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Test Code Epic LAB305 Coagulation Factor VII Activity Assay, Plasma

Additional Codes

SQ code F7M

Mayo code F_7

Reporting Name

Coag Factor VII Assay, P

Specimen Type

Plasma Na Cit

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Diagnosing congenital deficiency of coagulation factor VII

 

Evaluating acquired deficiencies associated with liver disease, oral anticoagulant therapy, and vitamin K deficiency

 

Determining degree of anticoagulation with warfarin to correlate with level of protein C

 

Investigation of a prolonged prothrombin time


Ordering Guidance


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.



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. (If not possible for medical reasons, note on request.)

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, -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.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reference Values

Adults: 65-180%

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

 

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

Day(s) Performed

Monday through Saturday

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.

CPT Code Information

85230

LOINC Code Information

Test ID Test Order Name Order LOINC Value
F_7 Coag Factor VII Assay, P 3198-9

 

Result ID Test Result Name Result LOINC Value
F_7 Coag Factor VII Assay, P 3198-9

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

Optical Clot-Based

Method Description

The factor VII assay is performed on the Instrumentation Laboratory ACL TOP using the prothrombin time (PT) method and a factor-deficient substrate. Patient plasma is combined and incubated with a factor VII-deficient substrate (normal plasma depleted of factor VII by immunoadsorption). After a specified incubation time, a PT reagent 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)

Report Available

1 to 3 days