Return to Test Directory
BETHESDA [FACTOR INHIBITOR ASSAY] (089-0418)
Test Mnemonic:

 Bethesda

Specimen Requirements:
Collection:

Blue-topped (3.2% sodium-citrate) tube. Routine venipuncture; discard 1st mL of blood by collecting a discard tube prior to collecting the blue-topped (3.2% sodium-citrate) tube.  For collections with butterfly blood collection sets, a discard tube should also be collected prior to collection of the blue top to ensure sufficient sample volume. Drawing a discard tube will displace the air from the blood collection set tubing to ensure proper blood draw volume.

Container:

 Blue-topped (3.2% sodium-citrate) tube

Storage/Transport:

NOTE: If delivery time is to be greater than 4 hours from time of draw, centrifuge the specimen for 15 minutes at 2000-2500g. 

·         Transfer plasma to 12x75 plastic tube

·         Cap tube and re-spin  for 15 minutes at 2000-2500g

·         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.

Specimen Preparation:

Samples should be received in laboratory within ½ hour of draw for best results.  Acceptable up to 4 hours after draw, at ROOM TEMPERATURE (20+/- 5°C).

Stability:

Whole blood 4 hours at room temperature. Plasma 4 hours at 20+/- 5°C. Frozen 15 days at -20°C, or 1 month at -80C. 

Causes for Rejection:

QNS, clotted, severely hemolyzed specimen, specimen greater than 4 hours old, wrong tube, high hematocrit (> 55%), sample identification error, sample processed/transported, and/or stored improperly

Reference Range:

Normal < 0.5 units Bethesda Units

Turnaround Time:

24 Hours

Methodology:

Electromagnetic Viscosity Detection

Performed:

Must be Scheduled with Hematology/Coagulation Laboratory at 409-772-2293. Performed on Day Shift only, Monday through Friday.

Synonyms:

MIXING STUDIES

Clinical Indication:

Measures levels of inhibitor of a specific factor (Factor VIII)

Patient Preparation :

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

CPT 4 Code:

85335

Note:

Interfering substances:  Replacement or anticoagulant therapy, presence of lupus anticoagulant

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-10 code or its verbal equivalent.
Return to Test Directory