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Clotting; factor II, prothrombin, specific

CPT4 code

Name of the Procedure:

Clotting; Factor II, Prothrombin, Specific Assay


The Clotting; Factor II, Prothrombin, Specific Assay is a blood test that measures the activity of prothrombin, a protein essential for blood clotting. This test helps diagnose certain bleeding disorders and monitor patients on anticoagulant therapy.


The medical condition or problem it addresses

The test is used to evaluate bleeding disorders and monitor the effectiveness and safety of anticoagulant medications such as warfarin.

The goals or expected outcomes of the procedure
  • To diagnose deficiencies or abnormalities in prothrombin (Factor II).
  • To adjust anticoagulant dosages for patients receiving blood-thinning medications.
  • To assess liver function as prothrombin is produced in the liver.


Specific symptoms or conditions that warrant the procedure
  • Unexplained bleeding or bruising
  • History of excessive bleeding during surgeries
  • Monitoring anticoagulant therapy (e.g., warfarin)
  • Suspected liver disease
Patient criteria or factors that make the procedure appropriate
  • Patients with a family history of bleeding disorders
  • Individuals currently on or starting anticoagulant therapy
  • Those with liver disease or conditions that might affect liver function


Pre-procedure instructions for the patient
  • No specific fasting required unless instructed otherwise by the healthcare provider.
  • Inform the healthcare provider of any medications being taken, especially anticoagulants and blood thinners.
  • Avoid certain medications and supplements that may affect clotting, as directed by the physician.
Any diagnostic tests or assessments required beforehand
  • Typically, a simple blood draw; other tests might include a complete blood count (CBC) or liver function tests if indicated.

Procedure Description

Detailed step-by-step explanation of what the procedure involves
  1. A healthcare professional will clean the site—usually the inside of the elbow or back of the hand—with an antiseptic.
  2. A tourniquet is applied to the upper arm to make the veins more visible.
  3. A needle is inserted into the vein to draw a blood sample.
  4. The sample is collected in a tube and sent to a laboratory for analysis.
Tools, equipment, or technology used
  • Sterile needle and syringe
  • Tourniquet
  • Collection tube
  • Analyzing equipment at the laboratory
Anesthesia or sedation details, if applicable
  • None required for this procedure.


  • The blood draw itself takes just a few minutes; results are typically available within a few days.


  • Performed in healthcare settings such as hospitals, outpatient clinics, and diagnostic laboratories.


  • Phlebotomist or nurse to collect the blood sample.
  • Laboratory technicians or medical technologists to analyze the sample.
  • Physician or specialist to interpret the results.

Risks and Complications

Common and rare risks associated with the procedure
  • Slight discomfort or bruising at the needle insertion site.
  • Rare risk of infection or excessive bleeding.
Possible complications and their management
  • Hematoma: Apply pressure and a cold pack to the area.
  • Infection: Maintain proper sterile techniques to minimize risk.


  • Accurate diagnosis of bleeding disorders.
  • Effective monitoring and management of anticoagulant therapy.
  • Timely detection of liver issues affecting clotting.


Post-procedure care and instructions
  • Keep the bandage on for a few hours to prevent bleeding.
  • Avoid heavy lifting or strenuous activity immediately after the blood draw.
Expected recovery time and any restrictions or follow-up appointments
  • Immediate; no significant recovery time needed.
  • Follow-up appointments based on initial results and ongoing monitoring needs.


Other treatment options available
  • Alternative clotting factor tests, such as Factor VIII or IX assays.
  • Traditional Prothrombin Time (PT) and International Normalized Ratio (INR) tests.
Pros and cons of alternatives compared to the described procedure
  • Other factor assays might gauge different clotting issues but won't provide specific information on prothrombin activity.
  • PT/INR tests are more commonly used for routine monitoring of warfarin therapy.

Patient Experience

What the patient might feel or experience during and after the procedure
  • Mild discomfort or a pinch when the needle is inserted.
  • Possible slight bruising or soreness at the puncture site.
Pain management and comfort measures
  • Inform patients about potential short-term discomfort and reassurances.
  • Advise patients to use over-the-counter pain relievers like acetaminophen if needed, but avoid aspirin which can affect clotting.

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