CPT® Code 85301

1. Indications

The CPT® Code 85301 is indicated for use in various clinical scenarios where the assessment of antithrombin III levels is necessary. This includes:

• Thrombosis Evaluation The procedure is performed to evaluate patients who have experienced thrombotic events, such as deep vein thrombosis or pulmonary embolism, to determine if antithrombin III deficiency is a contributing factor.
• Bleeding Disorders It is also indicated for patients presenting with unexplained bleeding, where antithrombin III levels may be implicated in the coagulation pathway.
• Monitoring Anticoagulant Therapy The assay is used to monitor patients undergoing anticoagulant therapy, particularly those receiving heparin, to ensure therapeutic levels of antithrombin III are maintained.
• Preoperative Assessment It may be indicated as part of a preoperative assessment in patients with a history of clotting disorders to evaluate their risk of perioperative thromboembolic complications.

2. Procedure

The procedure for CPT® Code 85301 involves several critical steps to accurately assess the level of antithrombin III activity in the blood sample. The first step is the collection of a diluted blood sample from the patient, which is essential for the subsequent analysis. This sample is then mixed with antithrombin-deficient plasma, which lacks the antithrombin III necessary for normal coagulation processes. The addition of intrinsic coagulation enzymes, an augmenting compound such as heparin, phospholipids, and an activator initiates the contact phase of the intrinsic coagulation pathway, setting the stage for the coagulation reaction. Following the preparation of this mixture, calcium ions are introduced to trigger the coagulation process. The time taken for coagulation to occur is meticulously measured and compared against a reference standard. This comparison allows for the determination of the antithrombin III activity level in the sample. In the specific method outlined for CPT® Code 85301, serum is added to a thrombin solution, and after a fixed incubation period, the residual thrombin activity in the plasma is measured. This step is crucial as it provides a direct assessment of the antithrombin III levels, which is vital for diagnosing and managing coagulation disorders.

3. Post-Procedure

After the completion of the CPT® Code 85301 procedure, the patient may not require any specific post-procedure care, as the assay is typically performed on an outpatient basis. However, it is essential for healthcare providers to monitor the patient for any potential adverse reactions, particularly if anticoagulant therapy is being adjusted based on the results of the assay. The results of the antithrombin III assay will be analyzed and interpreted by the healthcare provider, who will then discuss the findings with the patient and determine any necessary follow-up actions or treatments based on the antithrombin levels measured. It is also important to ensure that the patient understands the significance of the results and any implications for their ongoing management of coagulation disorders.