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EPIC ORDER CODE LAB305 Coagulation Factor VII Activity Assay, Plasma

Additional Codes

SQ: F7M

Reporting Name

Coag Factor VII Assay, P

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

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 Coagulation Consultation.



Necessary Information


 



Specimen Required


Specimen Type: Platelet-poor plasma

Patient Preparation:

1. Specimen must be collected prior to initiation of anticoagulants and thrombolytic therapy.

2. Patient must not be receiving warfarin, heparin, direct thrombin inhibitors (argatroban, dabigatran), or direct factor Xa inhibitors (apixaban, rivaroxaban, and edoxaban).

 a. If medically feasible, for 4 to 6 hours before specimen collection, do not administer intravenous heparin.

 b. If medically feasible, for 10 to 14 days before specimen collection, do not administer subcutaneous heparin or warfarin.

3. It is best to collect the specimen pretransfusion if possible. If patient has been recently transfused, wait at least 48 hours after transfusion to collect the specimen.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

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

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL Platelet-poor plasma

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 separate plastic vial, leaving 0.25 mL in the bottom of the centrifuged vial.

5. Immediately freeze plasma (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

Platelet-poor plasma: 0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
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

Clinical Information

Factor VII is a vitamin K-dependent serine protease synthesized in the liver. It is a component of the extrinsic coagulation scheme, measured by the prothrombin time. Plasma biological half-life is about 3 to 6 hours. Deficiency may result in a bleeding diathesis.

Interpretation

Liver disease, vitamin K deficiency, or warfarin anticoagulation can cause decreased factor VII activity.

 

Newborn infants usually have levels at or above 25%.

Clinical Reference

1. Girolami A, Scandellari R, Scapin M, Vettore S. Congenital bleeding disorders of the vitamin K-dependent clotting factors. Vitam Horm. 2008;78:281-374. doi:10.1016/S0083-6729(07)00014-3

2. Brenner B, Kuperman AA, Watzka M, Oldenburg J. Vitamin K-dependent coagulation factors deficiency. Semin Thromb Hemost. 2009;35(4):439-446. doi:10.1055/s-0029-1225766

3. Mariani G, Bernardi F. Factor VII deficiency. Semin Thromb Hemost. 2009;35(4):400-406. doi:10.1055/s-0029-1225762

4. Franchini M, Marano G, Pupella S, et al. Rare congenital bleeding disorders. Ann Transl Med. 2018;6(17):331. doi:10.21037/atm.2018.08.34

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; Cielsa B. Defects of plasma clotting factors. In: Hematology in Practice. 3rd ed. FA Davis; 2019:chap 17)

Report Available

1 to 3 days

Specimen Retention Time

7 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

Optical Clot-Based