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The CPT® Code 85246 refers to a laboratory test specifically designed to measure the levels of factor VIII and von Willebrand (VW) factor antigen in the blood. Factor VIII, also known as antihemophilic factor, is a crucial protein involved in the blood coagulation process. It works in conjunction with von Willebrand factor, which serves as a carrier protein for factor VIII, thereby stabilizing its activity in promoting blood clotting. Von Willebrand factor exists in two distinct forms: one that circulates freely in the plasma and another that is bound to the alpha granules of circulating platelets. The synthesis and release of plasma von Willebrand factor occur in the vascular endothelial cells, while the platelet-bound form is produced by megakaryocytes in the bone marrow. The test for VW factor antigen quantifies the mass of this antigen present in the blood; however, it is important to note that it does not assess the functional activity of von Willebrand factor. Decreased levels of VW factor antigen can indicate potential inherited disorders, such as congenital von Willebrand disease, or may arise from acquired conditions including monoclonal gammopathies, lymphoproliferative disorders, autoimmune diseases, or hypothyroidism. Conversely, elevated levels of VW factor antigen can be associated with various conditions, including pregnancy, estrogen use, acute phase inflammation, physical exercise, stress, liver disease, vasculitis, and thrombocytopenic purpura hemolytic uremic syndrome. This test is often ordered as part of the initial evaluation for von Willebrand disease. To perform the test, a blood sample is collected through a separately reportable venipuncture, and the analysis is conducted on platelet-poor plasma using a microlatex particle-mediated immunoassay.
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The test for factor VIII and von Willebrand factor antigen is indicated for various clinical scenarios, particularly when evaluating bleeding disorders. The following conditions may warrant the performance of this test:
The procedure for testing factor VIII and von Willebrand factor antigen involves several key steps to ensure accurate results. First, a blood sample is obtained from the patient through a venipuncture, which is a separately reportable procedure. This involves inserting a needle into a vein, typically in the arm, to collect the necessary blood volume. Once the blood is drawn, it is essential to process the sample correctly to obtain platelet-poor plasma. This is achieved by centrifuging the blood sample, which separates the plasma from the cellular components, including platelets. The resulting platelet-poor plasma is then used for the analysis. The test itself employs a microlatex particle-mediated immunoassay, a specific laboratory technique designed to quantify the amount of von Willebrand factor antigen present in the plasma. This method utilizes latex particles coated with antibodies that specifically bind to the VW factor antigen, allowing for the measurement of its concentration. The results of this test provide valuable information regarding the levels of von Willebrand factor antigen, which can aid in diagnosing and managing bleeding disorders.
After the venipuncture procedure, patients may experience minor discomfort or bruising at the site of blood collection, which typically resolves without intervention. There are no specific post-procedure care instructions required for the test itself, as it is a routine laboratory procedure. However, it is advisable for patients to remain hydrated and to inform their healthcare provider if they experience any unusual symptoms following the blood draw. The results of the VW factor antigen test are usually available within a few days, and healthcare providers will discuss the findings with the patient to determine any necessary follow-up actions or treatments based on the results.
| Short Descr | CLOT FACTOR VIII VW ANTIGEN | Medium Descr | CLOTTING FACTOR VIII VW FACTOR ANTIGEN | Long Descr | Clotting; factor VIII, VW factor antigen | Status Code | Statutory Exclusion (from MPFS, may be paid under other methodologies) | Global Days | XXX - Global Concept Does Not Apply | PC/TC Indicator (26, TC) | 9 - Not Applicable | Multiple Procedures (51) | 9 - Concept does not apply. | Bilateral Surgery (50) | 9 - Concept does not apply. | Physician Supervisions | 09 - Concept does not apply. | Assistant Surgeon (80, 82) | 9 - Concept does not apply. | Co-Surgeons (62) | 9 - Concept does not apply. | Team Surgery (66) | 9 - Concept does not apply. | Diagnostic Imaging Family | 99 - Concept Does Not Apply | CLIA Waived (QW) | No | APC Status Indicator | Conditionally packaged laboratory tests | Type of Service (TOS) | 5 - Diagnostic Laboratory | Berenson-Eggers TOS (BETOS) | T1H - Lab tests - other (non-Medicare fee schedule) | MUE | 2 | CCS Clinical Classification | 233 - Laboratory - Chemistry and Hematology |
| 90 | Reference (outside) laboratory: when laboratory procedures are performed by a party other than the treating or reporting physician or other qualified health care professional, the procedure may be identified by adding modifier 90 to the usual procedure number. | 91 | Repeat clinical diagnostic laboratory test: in the course of treatment of the patient, it may be necessary to repeat the same laboratory test on the same day to obtain subsequent (multiple) test results. under these circumstances, the laboratory test performed can be identified by its usual procedure number and the addition of modifier 91. note: this modifier may not be used when tests are rerun to confirm initial results; due to testing problems with specimens or equipment; or for any other reason when a normal, one-time, reportable result is all that is required. this modifier may not be used when other code(s) describe a series of test results (eg, glucose tolerance tests, evocative/suppression testing). this modifier may only be used for laboratory test(s) performed more than once on the same day on the same patient. | 59 | Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25. | GA | Waiver of liability statement issued as required by payer policy, individual case | GW | Service not related to the hospice patient's terminal condition | GY | Item or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit | GZ | Item or service expected to be denied as not reasonable and necessary | Q1 | Routine clinical service provided in a clinical research study that is in an approved clinical research study | Q4 | Service for ordering/referring physician qualifies as a service exemption | XU | Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service |
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| 2013-01-01 | Changed | Short Descriptor changed. |
| 1993-01-01 | Added | First appearance in code book in 1993. |
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