Test Overview
Test Methodology

Photo-optical determination of clot inhibition.

Test Usage

Detection of inhibitors directed against specific coagulation factors.

Reference Range *

Normal individuals have <0.5 Bethesda units. Critical value is >0.5 Bethesda units if no prior inhibitor has been detected.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Thursday, starting at 8am.
Analytic Time

3 hours

Soft Order Code
INH2, INH5, INH7, INH10, INH11, INH12
Synonyms
  • Bethesda Inhibitor
  • Coagulation Factor II Inhibitor Assay
  • Factor II Inhibitor Assay
  • Specific Factor Inhibitor Assay
  • Inhibitor Assay II:C
  • Inhibitor Assay V:C
  • Inhibitor Assay VII:C
  • Inhibitor Assay X:C
  • Inhibitor Assay XI:C
  • Inhibitor Assay XII:C
  • Coagulation Factor V Inhibitor Assay
  • Factor V Inhibitor Assay
  • Factor VII Inhibitor Assay
  • Coagulation Factor X Inhibitor Assay
  • Factor X Inhibitor Assay
  • Inhibitor Assay II, V, VII, X, XI, or XII
  • Coagulation Factor XI Inhibitor Assay
  • Factor XI Inhibitor Assay
  • Coagulation Factor XII Inhibitor Assay
  • Coagulation Factor VII Inhibitor Assay
  • Factor XII Inhibitor Assay
  • Factor 7 Inhibitor Assay
  • Factor 2 Inhibitor Assay
  • Factor 5 Inhibitor Assay
  • Factor 10 Inhibitor Assay
  • Factor 11 Inhibitor Assay
  • Factor 12 Inhibitor Assay
Laboratory
Hematopathology
Section
Coagulation
Specimen Requirements
Collection Instructions

The specific factor assay activity level is included in this order.If the factor activity level is >50%, the inhibitor level will not be performed. Collect specimen in two blue top (citrate 3.2%) tubes. Mix by inversion. Specimen should arrive at lab within 3 hours of collection; transport at room temperature. Alternatively, centrifuge, aliquot plasma from each blue top tube into separate plastic vials, and freeze the specimen within 4 hours of collection. Transport frozen specimen on dry ice. Collection of the blood through lines that have been previously flushed with heparin should be avoided. If the blood must be drawn through a VAD (vascular access device), the line should be flushed with 5 mL of saline and the first 5 mL of blood or six dead space volumes of the VAD discarded.

Contraindications
Test is not indicated if Factor level is greater than 50%, if the patient is receiving anticoagulation therapy, or if the patient is receiving factor replacement therapy.
Normal Volume
2 full 2.7mL tubes or 2mL of plasma (two 1 mL aliquots)
Minimum Volume
2 full 1.8mL tubes or 2mL of plasma (two 1 mL aliquots)
Storage Temperature
Room temperature for whole blood or frozen aliquot of citrated plasma.
Rejection Criteria
Specimens will be rejected if not properly filled, clotted, grossly hemolyzed, or contaminated with heparin.
Additional Information

The specific factor assay activity level will be performed concurrently with this assay and a separate charge generated. If the factor activity level is >50%, the inhibitor level will not be performed.

Billing
CPT Code
85335
Fee Code
31131
NY State Approved
No