Name of the Procedure:

Clotting; prekallikrein assay (Fletcher factor assay)

Summary

The prekallikrein assay, also known as the Fletcher factor assay, is a blood test used to measure the activity level of prekallikrein, a protein that plays a crucial role in the blood clotting process.

Purpose

The assay helps diagnose and evaluate bleeding disorders, particularly those related to abnormal blood clotting. Its primary goal is to detect prekallikrein deficiency, which can lead to prolonged bleeding times and other clotting abnormalities.

Indications

• Prolonged bleeding times
• Unexplained bruising
• Frequent nosebleeds
• Family history of clotting disorders
• Abnormal results in other clotting tests

Preparation

• Fasting is generally not required.
• Patients should inform their healthcare provider about any medications or supplements they are taking, as some substances can affect the test results.
• No specific diagnostic tests are needed beforehand, but a detailed medical history may be taken.

Procedure Description

1. Blood Sample Collection: A blood sample is drawn from a vein in the patient's arm.
2. Laboratory Analysis: The sample is sent to a laboratory where the activity level of prekallikrein is measured using specialized reagents and instruments.
3. Result Interpretation: The results are analyzed to determine if the prekallikrein activity is within the normal range.

The procedure involves standard phlebotomy equipment for blood collection and specific laboratory tools for the assay. No anesthesia or sedation is required.

Duration

The blood draw typically takes about 5-10 minutes. Laboratory analysis might take a few hours to a couple of days, depending on the lab's workload.

Setting

The blood sample is usually collected in a doctor's office, outpatient clinic, or laboratory setting.

Personnel

• 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

• Minor discomfort or bruising at the injection site
• Rare risk of infection
• Very low risk of fainting or hematoma

Benefits

• Accurate diagnosis of prekallikrein deficiency
• Better understanding of unexplained bleeding symptoms
• It guides appropriate treatment and management of clotting disorders

Recovery

No significant recovery time is needed. Patients can resume normal activities immediately after the blood draw. Follow-up appointments may be scheduled to discuss the results and next steps.

Alternatives

• Other clotting factor assays (e.g., Factor VIII or IX assays)
• Genetic testing for clotting disorders
• Comprehensive coagulation panel

Each alternative has its own pros and cons, with some providing a more detailed overview of clotting issues but may be more expensive or invasive.

Patient Experience

During the procedure, the patient might feel a minor prick or pinch when the needle is inserted for the blood draw. Post-procedure discomfort is usually minimal. Pain management and comfort measures, like applying a cold pack to the site, can help alleviate any minor soreness.