FLT3/ITD Allelic Ratio Test: Booking, Price, and Results

The FLT3/ITD Allelic Ratio Test is a specialised molecular test that detects and measures a specific genetic mutation in leukaemia cells. It analyses bone marrow or peripheral blood to determine the proportion of mutated FLT3 genes relative to normal ones. Doctors use this test primarily in patients diagnosed with or suspected of having acute myeloid leukaemia (AML). It is also referred to as the FLT3 Internal Tandem Duplication Ratio or ITD-AR Test.

This test is ordered for patients with newly diagnosed or relapsed AML to guide treatment planning and risk assessment. Here is when it is typically recommended.

Common Symptoms That May Require This Test

Doctors may order the FLT3/ITD Allelic Ratio Test when a patient presents with the following symptoms, which may point to AML:

• Persistent fatigue or weakness not explained by other causes
• Shortness of breath even with mild physical activity
• Unexplained bruising or bleeding
• Frequent infections due to a weakened immune system
• Pale skin related to low red blood cell counts
• Bone pain or tenderness
• Fever without an obvious cause

Conditions This Test Can Help Detect

The test is specifically used to assess the following:

• FLT3 internal tandem duplication (FLT3-ITD) mutation, found in approximately 20 to 30% of AML patients
• Prognostic risk category in AML (to estimate the likely disease outcome)
• Eligibility for targeted therapy using FLT3 inhibitor drugs
• Disease status at relapse, where the mutational pattern may have changed

No special preparation is needed for the FLT3/ITD Allelic Ratio Test procedure, but there are a few practical points to keep in mind before your appointment.

Do You Need to Fast?

No fasting is required for this test. You can eat and drink normally before your appointment.

Practical Tips Before Your Test

Keep the following in mind before sample collection:

• Bring a detailed clinical history, including your symptoms, previous test results, and any relevant medical records, as this information is required for the test.
• Inform your doctor or the collection team about any medications you are currently taking.
• Let your doctor know if you have had any recent infections or procedures, as these may affect the sample.
• Bone marrow aspirate is the preferred sample for the most accurate results; peripheral blood may be used if bone marrow cannot be collected.
• Samples should ideally contain at least 5% tumour cells for reliable detection.

Step-by-Step Procedure

Two types of samples may be collected for this test. Below is what you can expect for each.

Peripheral Blood Collection:

• A healthcare professional cleans the skin on your arm with an antiseptic wipe.
• A needle is gently inserted into a vein, usually in the inner elbow, to draw 3 ml of blood.
• The blood is collected into a lavender-top EDTA tube and labelled with your details.
• The needle is removed, and light pressure is applied to stop any minor bleeding.

Bone Marrow Aspirate Collection:

• You will be positioned lying down, and the skin over the collection site (typically the hip bone) is cleaned and numbed with a local anaesthetic.
• A specialist inserts a thin needle into the bone and withdraws a small amount of liquid bone marrow (approximately 3 ml), collected into a sodium heparin (green-top) tube.
• The site is cleaned and covered with a small dressing after collection.
• Both sample types are stored at 2 to 8°C and sent to the laboratory promptly, ideally within 48 hours of collection.
• In the lab, the sample undergoes fragment analysis, a method that uses polymerase chain reaction (PCR) and capillary electrophoresis to detect and measure the FLT3-ITD mutation.

Factors That Can Affect Accuracy

The following factors may influence the accuracy of your results:

• Low tumour cell content in the sample, which can underestimate the true allelic ratio
• Delays in sample transport or improper storage conditions
• The proportion of normal versus abnormal cells in the collected sample
• Laboratory methodology and equipment used for fragment analysis

Because this is a genetic mutation test used in cancer diagnosis and monitoring, the concept of "healthy levels" does not apply in the same way as routine blood tests. The following general points may support your overall well-being during treatment:

• Follow your haematologist's or oncologist's treatment and monitoring plan closely.
• Attend all scheduled follow-up appointments and repeat testing as advised by your medical team.
• Maintain a balanced diet and adequate rest to support your body during treatment.