Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test
About Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test
| Field | Value |
|---|---|
| Also Known As | Liquid Biopsy cfDNA EGFR Mutation Test, Cell-Free DNA EGFR Mutation Analysis, ctDNA EGFR Panel |
| Sample Type | Peripheral blood (collected in special cell-free DNA preservation tubes) |
| Fasting Required | No fasting required |
| Report Time | 15 days |
| Recommended For | Adults with non-small cell lung cancer (NSCLC), particularly those on or being considered for EGFR-targeted therapy |
| Price | Starting at ₹13,500 |
What Is a Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test?
The Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test is a blood-based genetic test that detects specific mutations in the EGFR (epidermal growth factor receptor) gene. It analyses fragments of tumour DNA that circulate freely in the bloodstream, making it a non-invasive alternative to a surgical tissue biopsy. This test is also known as the Liquid Biopsy cfDNA EGFR Mutation Test or ctDNA EGFR Panel. It is typically ordered for adults diagnosed with, or suspected to have, non-small cell lung cancer (NSCLC).
What Does a Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test Measure?
This test detects three specific mutations in the EGFR gene using a peripheral blood sample. Each mutation carries distinct clinical significance in lung cancer management.
The table below summarises what is analysed:
| Parameter | What It Detects | Why It Matters |
|---|---|---|
| Exon 19 Deletion (E746_A750del) | A deletion mutation in exon 19 of the EGFR gene | One of the most common activating EGFR mutations, may indicate responsiveness to targeted therapy |
| L858R Mutation (Exon 21) | A single point mutation in exon 21 | Another classical activating mutation that keeps cancer cell growth signals permanently switched on |
| T790M Mutation (Exon 20) | A resistance mutation in exon 20 | The most common reason first- and second-generation targeted therapies stop working; helps guide the switch to newer treatments |
Why Is a Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test Done?
This test plays an important role in guiding treatment decisions for lung cancer patients. It helps doctors identify which mutations are present so that the most appropriate therapy can be chosen.
Common Symptoms That May Require This Test
A doctor may order this test when a patient presents with the following symptoms:
- Persistent cough that does not resolve over several weeks
- Shortness of breath or difficulty breathing
- Coughing up blood or rust-coloured sputum
- Chest pain or discomfort
- Unexplained weight loss
- Hoarseness or changes in voice
- Unusual fatigue or generalised weakness
Conditions This Test Can Help Detect
This test is relevant to several specific clinical situations:
- Non-small cell lung cancer (NSCLC), which accounts for approximately 85% of all lung cancers
- Identification of patients with NSCLC who may benefit from EGFR-targeted therapies
- Detection of the T790M resistance mutation in patients whose cancer has progressed despite first- or second-generation targeted treatment
- Acquired resistance to ongoing therapy, helping doctors adjust the treatment plan accordingly
Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test for Chronic Disease Monitoring
For patients already on EGFR-targeted therapy, this test is an important tool for monitoring treatment response over time.
- Detecting the T790M mutation after first-line treatment is critical to prolonging survival in NSCLC patients with EGFR mutations.
- Serial testing may be recommended, as some patients who initially test negative may show a positive result on repeat testing within six months.
- Your oncologist will advise how often this test should be repeated based on your clinical progress.
How to Prepare and What to Expect
No special preparation is needed for this test, but a few practical steps will help ensure a smooth experience and a reliable sample.
Do You Need to Fast?
No, fasting is not required before this test. There are no dietary restrictions to follow. However, the timing of your sample collection is important, so always follow the guidance your doctor provides regarding when to get tested.
Practical Tips Before Your Test
A few simple steps can help ensure your sample is collected correctly:
- Bring a detailed clinical history including your symptoms, previous test results, and relevant medical records, as this is required for the test
- Inform your doctor about all current medications and any recent treatments or surgeries
- Stay well hydrated before your blood draw
- Let the phlebotomist (blood collection specialist) know if you have had recent chemotherapy, targeted therapy, or surgery, as these can affect cell-free DNA levels in the blood
Step-by-Step Procedure
The Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test procedure involves the following steps:
- A trained phlebotomist cleans the skin over a vein, usually in the arm, and collects a 10 ml peripheral blood sample.
- The blood is drawn into a special Streck Cell-Free DNA preservation tube (white-capped), which stabilises DNA fragments and prevents degradation.
- The sample is refrigerated at 2 to 8°C and dispatched to the laboratory on the same day.
- At the laboratory, the plasma is separated from blood cells by double centrifugation (spinning the sample twice at high speed).
- Cell-free DNA (tiny DNA fragments released by tumour cells into the blood) is extracted from the plasma.
- The extracted DNA is analysed using Droplet Digital PCR (a highly sensitive technique that detects very small amounts of specific mutations) to identify the presence or absence of the three EGFR mutations.
Factors That Can Affect Accuracy
Several factors can influence the reliability of this test:
- The type of blood collection tube used (special preservation tubes are essential)
- The time between blood collection and processing at the laboratory
- Tumour burden and disease stage (advanced disease typically sheds more tumour DNA into the blood)
- Recent surgery, chemotherapy, or high levels of inflammation, which can alter cell-free DNA levels
- Improper storage temperature of the sample before processing
Understanding Your Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test Results
This test reports qualitative results, meaning each mutation is reported as either "Detected" or "Not Detected". There are no numerical values. Your doctor will interpret the findings alongside your overall clinical picture.
| Parameter | Possible Result | Interpretation |
|---|---|---|
| Exon 19 Deletion | Not Detected / Detected | Qualitative result |
| L858R Mutation | Not Detected / Detected | Qualitative result |
| T790M Mutation | Not Detected / Detected | Qualitative result |
Disclaimer: These ranges are general guidelines. Your doctor will interpret your results based on your age, health history, and other factors. Always consult a qualified healthcare professional for personalised medical advice.
- A "Detected" result for Exon 19 deletion or L858R suggests the presence of activating EGFR mutations that may predict a good response to certain targeted therapies.
- A "Detected" result for T790M typically indicates that resistance to first- or second-generation targeted treatment has developed.
- A "Not Detected" result means these specific mutations were not found in the circulating tumour DNA at the time of testing; however, this does not always rule out their presence entirely, particularly in early-stage disease.
Results During Special Conditions
Certain clinical circumstances can influence how results are interpreted:
- Patients with metastases to the bone or liver tend to have higher amounts of tumour DNA in the blood, which may improve detection rates.
- Early-stage cancers may shed less tumour DNA, making mutations harder to detect compared to advanced disease.
- Recent treatment, surgery, or active inflammation can raise overall cell-free DNA levels, which may affect test interpretation.
How to Maintain Healthy Levels
This test detects genetic mutations rather than measuring a substance with a target range. The following general wellness steps support overall health during cancer care:
- Follow your oncologist's prescribed treatment plan consistently and attend all scheduled follow-up appointments.
- Report any new or changing symptoms to your healthcare team promptly, so monitoring can be adjusted if needed.
- Maintain a balanced diet and adequate rest to support your overall wellbeing during treatment.
Lupin Diagnostics Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test Price and Home Collection
The Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test is available at Lupin Diagnostics starting at ₹13,500, with home collection available across major Indian cities.
| City | Approximate Price (₹) |
|---|---|
| Mumbai | 13500 |
| Pune | 13500 |
| Bangalore | 13500 |
| Chennai | 13500 |
Disclaimer: Prices are indicative and may vary by location. Please confirm the current price at the time of booking.
How to Book
Booking your Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test online is straightforward:
- Select the test on the Lupin Diagnostics website.
- Choose your city and preferred time slot.
- Opt for home sample collection by a certified phlebotomist, or visit your nearest Lupin Diagnostics centre.
- Receive your report via email or WhatsApp within the stipulated turnaround time.
Home Collection
Lupin Diagnostics offers Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test home collection across cities, where a trained phlebotomist visits your home to collect the peripheral blood sample using the required preservation tube. All samples are processed in NABL-accredited laboratories by experienced scientists. Digital reports are delivered securely via email or WhatsApp once ready.
Frequently Asked Questions
A tissue biopsy involves surgically removing a sample of tumour tissue for analysis. A liquid biopsy EGFR test instead analyses tiny fragments of tumour DNA that circulate in the blood, making it a far less invasive option. This approach reduces patient discomfort and avoids the complications associated with surgical procedures.
This test is recommended for adults diagnosed with non-small cell lung cancer, particularly those being considered for EGFR-targeted therapy or whose cancer has progressed during existing treatment. EGFR mutation testing is also recommended at the time of diagnosis for patients with lung adenocarcinoma (a type of lung cancer). Your doctor will advise whether this test is appropriate for you.
The T790M mutation is the most common reason why first- and second-generation EGFR-targeted treatments stop working. Detecting this mutation allows doctors to consider switching to third-generation treatments that are specifically designed to overcome this resistance. Early detection through the Liquid Bx. Cell Free EGFR test supports timely changes to the treatment plan.
Not definitively. Liquid biopsy is highly sensitive, but false negative results can occur, particularly in early-stage cancers where tumour DNA shedding into the blood may be low. If your result is negative but your doctor still suspects an EGFR mutation, a tissue biopsy may be recommended as a follow-up.
Yes. EGFR mutations are significantly more common in Asian patients with NSCLC, with a prevalence of approximately 49% compared to around 12 to 33% in other regions. These mutations are also more frequently seen in people who have never smoked or have a limited smoking history.
Results for the Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] test are typically delivered within 15 days from the time the sample is received at the laboratory. This is generally faster than a conventional tissue biopsy, which can take several weeks.
The frequency of repeat testing depends on your individual treatment response and clinical progression. Your oncologist will advise on the appropriate schedule. Research indicates that some patients who initially test negative may test positive on repeat testing within six months, making periodic monitoring valuable.
Liquid Bx. Cell-Free EGFR [T790M, L858R, Exon 19 deletion] Test
