Laboratory Test Directory

BETHESDA  [FACTOR INHIBITOR ASSAY] :(089-0418)

Clinical Indication:

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

Test Mnemonic:

 Bethesda

Methodology:

 Electromagnetic Viscosity Detection

Performed:

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

Turnaround Time:

24 Hours

Specimen Requirements:

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

Collect: 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.

Specimen Preparation: Samples should be received in laboratory within ½ hour of draw for best results.  Acceptable up to4 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 specimen for 15 minutes at 2000-2500g.  Separate the plasma from the cells and freeze (-20⁰C) the plasma.

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 (3.8% sodium citrate), high hematocrit (> 55%), identification error, sample processed/transported, and/or stored improperly

Clinical Information:

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

Reference Range:

Normal < 0.5 units Bethesda Units

Note:

CPT 4 Code:

 85335

Review

 12/12/12 by A. Huerta. BS, MT( ASCP), MBA

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.