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Test Code 035 Inhibitor Screen (Circulating Anticoagulants)

Important Note

If studies for Lupus Anticoagulant are requested refer to Dilute Viper Venom Test (435) and Cardiolipin Antibodies (CLPMG)Test.

Additional Codes


PowerChart: Inhibitor Screen

Epic: LAB2355 Circulating Anticoagulant

MA Cerner: Inhibitor Screen.

Test Method

APTT or Prothrombin-Based Clot Detection After Addition of Normal Patient Plasma; Beckman Coulter

Specimen Requirement

Sodium citrate blue-top tube filled to the area within the indicator arrow printed on the side of the tube.

Additional Specimen Collection Information

Specimen is stable up to 4 hours after collection if refrigerated and unopened. Hemolyzed specimens are unacceptable.

If testing cannot be completed within 4 hours of collection:

  1. Centrifuge the specimen for 15 minutes at 1800 RCF
  2. Remove the platelet-poor plasma from the cells.
  3. Transfer the plasma to a plastic tube and cap the tube.
  4. Freeze the plasma sample. Frozen samples are stable for up to 2 weeks.


Testing is performed Monday through Sunday.

Typically completed within 4 hours after the specimen arrives at the testing site.

Reference Values

Circulating Anticoagulants: Negative

CPT Code Information

85732 APTT

85611 Prothrombine Time

Useful For

Screening assay to detect coagulation inhibition ("circulating anticoagulants") associated with:

-Specific coagulation factor inhibitors

-Lupus-like anticoagulant inhibitors (antiphospholipid antibodies)

-Nonspecific prothrombin time inhibitors (eg, monoclonal immunoglobulins, elevated fibrin degradation products)

LOINC Code Information

34570-2 Lupus Anticoagulant Neutralization High Phospholipid.Factor Substitution [Time] In Platelet Poor Plasma By Coagulation Assay-Immediately After 1:2 Addition Of Normal Plasma