2025 CPT code 85300
(Active) Effective Date: N/A Pathology and Laboratory Procedures - Hematology and Coagulation Procedures Feed
Assay of antithrombin III activity.
Modifiers may be applicable.Modifier 91 is used for repeat testing.Modifier 90 indicates testing performed by an outside laboratory.
Medical necessity is established by the patient's clinical presentation and the physician's suspicion of antithrombin III deficiency, related to conditions such as recurrent thrombosis, heparin therapy, liver disease, or other relevant clinical scenarios.
The laboratory analyst performs all technical steps involved in the assay.
In simple words: This is a blood test that checks how well a protein called antithrombin III is working in your body.Antithrombin III helps prevent blood clots, so this test is done to see if you might be at risk for developing dangerous clots.
This code represents the laboratory test to evaluate the activity of antithrombin III in a patient's plasma.It is used to determine if a patient is deficient in antithrombin III activity, which can be due to either genetic or acquired conditions. The test may involve incubating patient plasma with factor Xa and excess heparin, and then measuring residual factor Xa, often using a chromogenic assay. Since antithrombin III inhibits factor Xa, this test can identify antithrombin III deficiency.
Example 1: A patient presents with recurrent deep vein thrombosis.The physician orders an antithrombin III activity assay (85300) to investigate the possibility of a congenital or acquired antithrombin III deficiency., A patient is undergoing heparin therapy.To monitor the effectiveness of the treatment and assess for potential heparin-induced antithrombin III deficiency, the physician orders an antithrombin III activity assay (85300)., A patient with liver disease is experiencing unusual bleeding.The physician orders an antithrombin III activity assay (85300) to evaluate the patient's coagulation status and determine if antithrombin III deficiency is contributing to the bleeding.
Documentation should include the reason for the test, relevant clinical findings, and any related diagnoses or conditions.
- Revenue Code: T1H (LAB TESTS - OTHER (NON-MEDICARE FEE SCHEDULE))
- Specialties:Hematology, Pathology
- Place of Service:Independent Laboratory, Hospital, Office