CPT® Code 85730

The CPT® Code 85730 refers to the laboratory test known as the partial thromboplastin time (PTT), which can be performed on either plasma or whole blood samples. This test is crucial in the assessment of the blood's ability to clot properly and is often utilized in various clinical scenarios. Commonly referred to as activated PTT or aPTT, this test is primarily conducted to diagnose the underlying causes of bleeding disorders or as a precautionary measure before surgical procedures to exclude any potential coagulation defects. The methodology involves mixing a specific reagent containing silica and synthetic phospholipids with the patient's plasma. The silica acts as a negatively charged surface that activates the contact pathway of the coagulation cascade. Following this activation, calcium chloride is added to the mixture to initiate the clotting process. The time taken for clot formation is then measured using photo-optical methods, providing a quantitative assessment of the coagulation status. In cases where the PTT results are elevated and the patient is not on anticoagulant therapy, a follow-up test known as a PTT mixing study may be indicated. This involves mixing the patient's plasma with normal plasma in a 1:1 ratio and re-evaluating the clotting time. The outcomes of this mixing study can help determine whether the elevation in PTT is due to the presence of an inhibitor, such as lupus anticoagulant, or a deficiency in coagulation factors.