Factor VII Activity

Casandra

Casandra Test Code LC30388Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 800599CPT Code 85230

Also known as: Proconvertin

Clinical Use

Order Test

Use

Evaluate an isolated prolonged PT and document factor VII deficiency6-8

Special Instructions

If the patient's hematocrit exceeds 55%, the volume of citrate in the collection tube must be adjusted. Refer to Coagulation Collection Procedures for directions. Ideally, the patient should not be on anticoagulant therapy. Avoid warfarin therapy for two weeks prior to the test and heparin, direct Xa, and thrombin inhibitor therapies for about three days prior to testing. Do not draw from an arm with a heparin lock or heparinized catheter.

Limitations

Direct Xa or thrombin inhibitor therapy may cause factitiously low results. Artifactual elevations in factor VII can occur as the result of cold activation of factor VII in the collection tube prior to analysis. Refrigerating or placing the sample on ice for an extended period prior to freezing the plasma can result in the conversion of factor VII to activated factor VIIa.

Test Details

Methodology

Other

Biomarkers

Factor VII

Protein

Factor VII Activity • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Order Codes

3198-9

Result Codes

3198-9

Result Turnaround Time

2-3 days

Specimen

Plasma

Volume

1 mL

Minimum Volume

Not provided

Container

Blue-top (sodium citrate) tube

Collection Instructions

Blood should be collected in a blue-top tube containing 3.2% buffered sodium citrate. Evacuated collection tubes must be filled to completion to ensure a proper blood-to-anticoagulant ratio. The sample should be mixed immediately by gentle inversion at least six times. A discard tube is required if using a winged collection set.

Patient Preparation

Avoid warfarin (Coumadin®) therapy for two weeks prior, and heparin, direct Xa, and thrombin inhibitors for about three days prior to testing. Do not draw from an arm with a heparin lock or heparinized catheter.