Laboratory Test Directory

FACTOR VII ASSAY: (089-0009)

Clinical Indication:

 Measures levels of factor(s) that can be useful in diagnosing bleeding disorders and liver disease.

Test Mnemonic:

 FACTORVII

Methodology:

  Electromagnetic Viscosity Detection

Performed:

 Samples are accepted 24 hours per day at Sample Management, 5.136 McCullough Bldg.

Turnaround Time:

 STAT: 1 1/2 hours; ROUTINE: 4 hours

Specimen Requirements:

Patient Preparation: Patient must not be on any anticoagulation therapy for 48 hours before blood collection.

Collect: Routine venipuncture; discard 1st mL of blood or collect other tubes (EDTA, red-topped) prior to collecting sample in (2) blue-topped (3.2% sodium-citrate) tubes. 

If drawing from a blood collection set, draw a discard tube. This will displace the air from the blood collection set tubing to ensure proper blood draw volume. Pulling in this air will result in under filling the tube, thus causing an incorrect blood-to-additive ratio.

Specimen Preparation:  Acceptable up to 4 hours after draw, at ROOM TEMPERATURE.

Storage/Transport:  NOTE: If delivery time is to be greater than 4 hours from time of draw, centrifuge the sample at 2000 - 2500g for 10 minutes.

·         Transfer plasma to 12x75 plastic tube

·         Cap tube and re-spin  at 2000 - 2500g for 10 minutes

·         CAREFULLY remove from centrifuge without disturbing any platelets and/or cell pellets that might be on the bottom or sides of the tube.

·         Carefully transfer plasma into freezer tubes (plastic screw-top cryo-tubes) for testing or freezing .

 *Do not keep plasma at 2-8⁰C because the factor VII can be activated by kallikrein system in this temperature range.

Stability:  Whole blood 4 hours at room temperature.   Plasma is stable for 4 hours at 20+  5⁰C.   Frozen plasma 1 month at -20C.

Causes for Rejection: QNS, clotted, severely hemolyzed specimen, specimen greater than 4 hours old, wrong tube (3.8% sodium citrate), high hematocrit (> 55%), sample identification error, sample processed/transported, and/or stored improperly.

Clinical Information:

Interfering substances:  oral contraceptives, anticoagulant therapy, thrombin inhibitors.

Reference Range:

0.67 - 1.54 Units

Note:

CPT 4 Code:

 85230

 Reviewed: 3/20/13

W.Russo, MT(ASCP)

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient.  Components of the organ or disease panels may be ordered individually.  The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-9 code or its verbal equivalent.