2025 CPT code 85301
(Active) Effective Date: N/A Revision Date: N/A Pathology and Laboratory Procedures - Anticoagulant Assays Hematology and Coagulation Procedures Feed
This CPT code represents an antithrombin III antigen assay, a laboratory test measuring the amount of antithrombin III protein in a plasma sample.
Modifiers may apply depending on the circumstances of service. Consult payer-specific guidelines for modifier usage.
Medical necessity for 85301 is established based on the patient's clinical presentation, risk factors for thrombotic events, and results of other coagulation studies. Abnormal findings from antithrombin III activity tests or a suspicion of inherited or acquired antithrombin deficiency warrant this testing.
The clinical responsibility rests with the laboratory personnel who perform the test, analyze the results, and report them to the ordering physician. The ordering physician interprets the results within the context of the patient's clinical presentation and other diagnostic information.
In simple words: This blood test measures the level of a protein called antithrombin III in your blood.Antithrombin III helps prevent blood clots.A low level might mean you have a higher risk of blood clots.
CPT code 85301 describes a laboratory procedure to quantitatively determine the concentration of antithrombin III (AT III) antigen in a patient's plasma.The test utilizes an antigen-antibody reaction, typically employing techniques like an ELISA (enzyme-linked immunosorbent assay) or latex agglutination. This assay measures the total amount of AT III protein, regardless of its functionality. The results aid in diagnosing antithrombin III deficiency, which can be congenital or acquired (e.g., due to liver disease, heparin therapy, or certain chemotherapies).Clinicians frequently order this test to investigate abnormal results from antithrombin III activity assays (CPT code 85300) or to evaluate individuals with a high risk of thrombotic events.
Example 1: A patient presents with recurrent deep vein thrombosis (DVT). An antithrombin III activity test (85300) reveals low activity.The physician orders 85301 to differentiate between type I (low antigen and activity) and type II (low activity, normal antigen) antithrombin deficiency., A patient receiving heparin therapy for atrial fibrillation experiences unexplained bleeding. The physician orders 85301 to assess for potential heparin-induced antithrombin III deficiency., A patient with a family history of thromboembolic disease undergoes pre-surgical screening.As part of the work-up, the physician orders 85301 to assess their baseline antithrombin III level.
* Physician's order specifying the test (85301).* Patient demographics and relevant medical history (including medication history and any existing clotting disorders).* Properly collected and labeled plasma sample.* Laboratory report detailing the quantitative results of the antithrombin III antigen assay.
** Acquired antithrombin III deficiency is more common than inherited deficiency and can occur due to factors such as liver disease, disseminated intravascular coagulation, and certain medications (heparin, L-asparaginase).Heparin therapy may interfere with the test results, but other anticoagulants typically do not.Consult the laboratory's test ordering guidelines for specific details regarding specimen collection and handling.
- Revenue Code: T1H (LAB TESTS - OTHER (NON-MEDICARE FEE SCHEDULE))
- RVU: Information not available in source data.RVUs vary by payer and geographic location.
- Global Days: Not applicable. This is a laboratory test, not a surgical procedure.
- Payment Status: Active
- Modifier TC rule: Not applicable. This is a laboratory test, not a surgical procedure with a technical component.
- Fee Schedule: Information not available in source data.Fee schedules vary by payer and geographic location.
- Specialties:Hematology, Thrombosis, Clinical Pathology
- Place of Service:Office, Hospital, Laboratory