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Protein C is a vital component of the body's natural anticoagulation system, playing a crucial role in regulating blood clotting. Deficiencies in protein C can lead to serious health issues, including recurrent thrombosis, which is the formation of blood clots in veins, and warfarin-induced skin necrosis, a condition where skin tissue dies due to inadequate blood supply. The CPT® Code 85303 specifically refers to the measurement of protein C activity in a patient's blood sample. This process involves diluting the blood sample and adding sodium citrate or citric acid to prevent clotting. The sample is then incubated in microwells that are coated with antibodies specific to human protein C, allowing the protein C present in the sample to bind to these antibodies. Following this binding phase, a detection antibody conjugated with horseradish peroxidase (HRP) is introduced. After washing away any unbound detection antibodies, a chromogenic substrate is added, which reacts to produce a colored product. The intensity of this color is then measured, providing a quantitative assessment of protein C activity. The primary purpose of ordering this assay is to evaluate whether a patient has a deficiency in protein C, which can significantly increase their risk for developing venous thromboembolism, a serious condition characterized by blood clots in the veins.
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Protein C activity measurement is indicated for patients who may be at risk for thrombotic events due to deficiencies in coagulation control. The following conditions warrant the ordering of this test:
The procedure for measuring protein C activity involves several critical steps to ensure accurate results. First, a blood sample is collected from the patient and then diluted appropriately. Following dilution, sodium citrate or citric acid is added to the sample to prevent coagulation during the testing process. The diluted sample is then placed in microwells that have been pre-coated with antibodies specific to human protein C. This incubation allows the protein C present in the patient's sample to bind to the antibodies on the well surface. After the binding period, a detection antibody that is conjugated with horseradish peroxidase (HRP) is added to the wells. This detection antibody specifically targets the bound protein C. After allowing sufficient time for the reaction, the wells are washed thoroughly to remove any unbound detection antibodies, ensuring that only the bound complexes remain. Subsequently, a chromogenic substrate is introduced to the wells, which reacts with the HRP enzyme to produce a soluble colored product. The intensity of the color produced is directly proportional to the amount of protein C activity in the sample and is measured using a spectrophotometer. This quantitative measurement provides essential information regarding the patient's protein C levels.
After the protein C activity assay is completed, the results are analyzed to determine the patient's protein C levels. If a deficiency is identified, further clinical evaluation and management may be necessary to address the increased risk of venous thromboembolism. It is important for healthcare providers to interpret the results in conjunction with the patient's clinical history and other laboratory findings. Patients may not require specific post-procedure care, but they should be monitored for any symptoms related to coagulation disorders, especially if they have a history of thrombotic events. Follow-up consultations may be scheduled to discuss the results and potential treatment options if a deficiency is confirmed.
| Short Descr | CLOT INHIBIT PROT C ACTIVITY | Medium Descr | CLOTTING INHIBITORS PROTEIN C ACTIVITY | Long Descr | Clotting inhibitors or anticoagulants; protein C, activity | 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. | Q4 | Service for ordering/referring physician qualifies as a service exemption | 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. | 26 | Professional component: certain procedures are a combination of a physician or other qualified health care professional component and a technical component. when the physician or other qualified health care professional component is reported separately, the service may be identified by adding modifier 26 to the usual procedure number. | 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 | 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 |
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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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