How To Use CPT Code 85303

CPT 85303 describes the test to evaluate the activity of protein C 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 85303?

CPT 85303 can be used to describe the test performed by a lab analyst to evaluate the activity of protein C in a patient’s plasma. This test helps determine if the patient has reduced protein C activity, which can be caused by genetic or acquired conditions. The test involves combining the patient’s plasma with a specific protein C activator enzyme and measuring the rate of clotting through a color change in the test substrate.

2. Official Description

The official description of CPT code 85303 is: ‘Clotting inhibitors or anticoagulants; protein C, activity.’

3. Procedure

1. The lab analyst performs all technical steps to evaluate the activity of protein C in the patient’s plasma.
2. The test may involve combining the patient’s plasma with a specific protein C activator enzyme and measuring the rate of clotting through a color change in the test substrate.
3. The lab analyst determines if the patient has reduced protein C activity, either due to genetic or acquired conditions.

4. Qualifying circumstances

CPT 85303 is used when a clinician orders the test to evaluate patients with a family or personal history suspicious for congenital protein C deficiency. It can also be used to identify acquired functional protein C deficiency due to conditions such as oral anticoagulant use, vitamin K deficiency, or liver disease.

5. When to use CPT code 85303

CPT code 85303 should be used when a clinician orders the test to evaluate the activity of protein C in a patient’s plasma. It is not limited to testing for a specific condition but is commonly used to assess patients with suspected congenital or acquired protein C deficiency.

6. Documentation requirements

To support a claim for CPT 85303, the documentation should include:

• Reason for ordering the test, such as family or personal history suspicious for congenital protein C deficiency
• Results of the protein C activity test
• Any additional relevant information, such as the patient’s medication use or liver function

7. Billing guidelines

When billing for CPT 85303, ensure that the test is performed by a lab analyst and that the documentation supports the medical necessity of the test. It is important to distinguish CPT 85303 from other related codes, such as protein C antigen assay (CPT 85302) and activated protein C resistance test (CPT 85307). Additionally, some payers may separately reimburse for the collection of the specimen using a code such as 36415 for venipuncture.

8. Historical information

CPT 85303 was added to the Current Procedural Terminology system on January 1, 1993. There have been no updates to the code since its addition.

9. Examples

1. A lab analyst performing a protein C activity test to evaluate a patient with a suspected congenital protein C deficiency.
2. A clinician ordering a protein C activity test for a patient with a personal history of oral anticoagulant use to assess for acquired protein C deficiency.
3. A lab analyst evaluating the activity of protein C in a patient’s plasma to determine the effectiveness of vitamin K supplementation.
4. A clinician ordering a protein C activity test for a patient with liver disease to assess for acquired protein C deficiency.
5. A lab analyst performing a protein C activity test to evaluate a patient with a family history of thrombosis and suspected congenital protein C deficiency.
6. A clinician ordering a protein C activity test for a patient with unexplained recurrent venous thromboembolism to assess for acquired protein C deficiency.
7. A lab analyst evaluating the activity of protein C in a patient’s plasma to monitor the effectiveness of anticoagulant therapy.
8. A clinician ordering a protein C activity test for a patient with a suspected acquired protein C deficiency due to vitamin K deficiency.
9. A lab analyst performing a protein C activity test to evaluate a patient with a family history of protein C deficiency and suspected congenital protein C deficiency.
10. A clinician ordering a protein C activity test for a patient with a suspected acquired protein C deficiency due to liver disease.