Inhibitor Assay, PTT with Reflex to PTT 1:1 Mix, with Reflex to 1-Hour Incubation

Casandra

Casandra Test Code AR39388Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 2003266CPT Codes 85730, 85732

Inhibitor Assay, PTT with Reflex to PTT 1:1 Mix, with Reflex to 1-Hour Incubation

Also known as: PTT INHIB

Clinical Use

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Use

The Inhibitor Assay, PTT with Reflex to PTT 1:1 Mix, with Reflex to 1-Hour Incubation is used for the initial screening for inhibitors in plasma. This assay is particularly useful in identifying coagulation factor deficiencies which can cause bleeding disorders. It helps in diagnosing inhibitors like lupus anticoagulants, specific factor inhibitors, as well as the effects of anticoagulation medications such as heparin. When a prolonged PTT is detected, a mixing study is performed to help differentiate between factor deficiencies and inhibitors.

Special Instructions

This test requires collection of plasma in a light blue (sodium citrate) top tube. It is crucial to submit separate specimens when multiple tests are ordered to ensure sample integrity. The specimen must be critically frozen during storage and transport to preserve its stability.

Limitations

The test is unable to provide accurate results if the specimen is serum or EDTA plasma, or if the sample is clotted or hemolyzed. Additionally, the results of the PTT test can be affected by anticoagulant medications, and therefore the test should be interpreted with clinical correlation. The test cannot directly diagnose specific coagulation disorders without additional confirmatory tests.

Test Details

New York Approved