Factor inhibitor test
CPT4 code
Name of the Procedure:
Factor Inhibitor Test (also known as Factor Neutralization Assay, Factor VIII Inhibitor Test)
Summary
A Factor Inhibitor Test is a blood test used to identify inhibitors that may interfere with the action of specific clotting factors, primarily Factor VIII. This helps diagnose and manage conditions related to abnormal blood clotting.
Purpose
The test addresses bleeding disorders, particularly hemophilia, by detecting antibodies that inhibit clotting factors. The goal is to confirm the presence of these inhibitors and assess their impact on blood clotting efficiency.
Indications
- Frequent and unexplained bleeding episodes
- Known hemophilia patients with reduced effectiveness of clotting factor replacement therapy
- Unexpected bleeding during surgery or trauma in a known hemophilia patient
Preparation
- No fasting required
- Inform the healthcare provider about all medications and supplements being taken
- Diagnostic tests like complete blood count (CBC) may be conducted beforehand
Procedure Description
- Blood Sample Collection: A healthcare provider draws a blood sample from a vein, usually in the arm.
- Testing: The blood sample is sent to the lab where it is mixed with specific clotting factors to measure the presence and activity of any inhibitors.
- Analysis: Laboratory analysis determines the potency of inhibitors by measuring clotting time and comparing it to standard values.
Tools: Blood collection needles, vacutainer tubes, laboratory reagents. Anesthesia: Not required, though local numbing cream might be applied in rare cases.
Duration
The blood draw takes about 10-15 minutes. Laboratory analysis may take a few hours to a few days, depending on the facility.
Setting
The procedure is performed in a hospital, outpatient clinic, or specialized laboratory setting.
Personnel
- Phlebotomist or nurse for blood draw
- Laboratory technician or specialist for sample analysis
- Hematologist or physician to interpret results
Risks and Complications
- Common: Minor bruising or discomfort at the blood draw site.
- Rare: Infection at puncture site, dizziness or fainting, incorrect sample handling leading to inaccurate results.
Benefits
Early and accurate identification of inhibitors allows for better management of bleeding disorders and tailored treatment plans. Benefits are typically realized almost immediately with proper medical intervention.
Recovery
- Post-procedure care: Apply pressure to the puncture site to reduce bleeding.
- Recovery time: Immediate; normal activities can usually be resumed right after.
Alternatives
- Mixing study (an alternative blood test to assess clotting function)
- Genetic testing for clotting disorders
- Pros and cons: Mixing studies provide rapid results but may not be as specific; genetic testing offers comprehensive insight but is more expensive and time-consuming.
Patient Experience
- During the procedure: A brief pinching sensation from the needle.
- After the procedure: Slight tenderness at the puncture site, manageable with over-the-counter pain relief if necessary.
- Pain management: Usually not required due to the minimally invasive nature of the blood draw.