How To Use CPT Code 85300

CPT 85300 describes the evaluation of antithrombin III activity in a patient’s plasma. This article will cover the description, procedure, qualifying circumstances, appropriate usage, documentation requirements, billing guidelines, historical information, similar codes and billing examples.

1. What is CPT Code 85300?

CPT 85300 is used to evaluate the activity of antithrombin III in a patient’s plasma. This test is performed by a lab analyst to determine if the patient has a deficiency in antithrombin III activity, which can be caused by genetic or acquired conditions. The test involves incubating the patient’s plasma with factor Xa and excess heparin, and measuring residual factor Xa, often using a chromogenic assay. By inhibiting factor Xa, antithrombin III deficiency can be detected. This test is not limited to a specific condition but is commonly ordered to diagnose acquired or congenital antithrombin III deficiency, which may be associated with deep vein thrombosis (DVT) and pulmonary embolism (PE). Acquired deficiencies can occur due to heparin therapy, liver disease, or certain chemotherapies.

2. Official Description

The official description of CPT code 85300 is: ‘Clotting inhibitors or anticoagulants; antithrombin III, activity.’

3. Procedure

1. The lab analyst performs all technical steps to evaluate the activity of antithrombin III in the patient’s plasma.
2. This may include incubating the patient’s plasma with factor Xa and excess heparin, and measuring residual factor Xa using a chromogenic assay.
3. Other factors, such as heparin cofactor II, alpha–2–macroglobulin, or alpha–1–antitrypsin, may influence the test results and should be taken into account.

4. Qualifying circumstances

CPT 85300 is used when there is a clinical suspicion of antithrombin III deficiency, either congenital or acquired. Patients with conditions such as deep vein thrombosis (DVT) or pulmonary embolism (PE) may require this test to determine if antithrombin III activity is a contributing factor. The test is performed by a lab analyst and does not require any specific qualifications for the healthcare professional ordering the test.

5. When to use CPT code 85300

CPT code 85300 should be used when evaluating the activity of antithrombin III in a patient’s plasma. It is appropriate to order this test when there is a clinical suspicion of antithrombin III deficiency, either congenital or acquired, and when the results of the test will contribute to the diagnosis or management of the patient’s condition.

6. Documentation requirements

To support a claim for CPT code 85300, the following documentation is required:

• Clinical indication for ordering the test
• Results of the antithrombin III activity evaluation
• Any relevant factors that may influence the test results

7. Billing guidelines

When billing for CPT code 85300, ensure that the test is performed by a lab analyst and that the documentation supports the medical necessity of the test. There are no specific billing guidelines or modifiers associated with this code.

8. Historical information

CPT code 85300 was added to the Current Procedural Terminology system on January 1, 1990. There have been no updates or changes to the code since its addition.

9. Examples

1. A patient with a history of deep vein thrombosis (DVT) and pulmonary embolism (PE) undergoes an antithrombin III activity evaluation to determine if antithrombin III deficiency is a contributing factor.
2. A patient receiving heparin therapy requires an antithrombin III activity evaluation to monitor their response to the treatment.
3. A patient with liver disease undergoes an antithrombin III activity evaluation to assess their risk of developing blood clots.
4. A patient undergoing chemotherapy requires an antithrombin III activity evaluation to monitor their coagulation status.
5. A patient with a family history of antithrombin III deficiency undergoes an antithrombin III activity evaluation as a precautionary measure.
6. A patient with unexplained recurrent blood clots undergoes an antithrombin III activity evaluation to identify any underlying clotting disorders.
7. A patient with a suspected acquired antithrombin III deficiency due to heparin therapy undergoes an antithrombin III activity evaluation to confirm the diagnosis.
8. A patient with a suspected congenital antithrombin III deficiency undergoes an antithrombin III activity evaluation to establish a baseline for their condition.
9. A patient with a history of thrombophilia undergoes an antithrombin III activity evaluation to assess their risk of developing blood clots.
10. A patient with a suspected antithrombin III deficiency undergoes an antithrombin III activity evaluation to guide their treatment plan.