What is a Liquid Biopsy Test for Cancer Detection?

What is Liquid Biopsy?

Liquid Biopsy According to the Oxford Dictionary Liquid biopsy means a test that enables the doctor to diagnose and analysis of tumours by using only fluid or blood samples instead of the usual solid tissue biopsy.

A liquid biopsy test for cancer is an elaborate test that can detect cancerous cell DNA and tumour cells. As of now, it’s possible to detect certain forms of advanced cancers, provide prognosis and eventually help healthcare professionals to decide on the necessary course of action. This is a major leap in the advancement of medical practices as earlier methods required patients to submit a solid tissue for biopsy. This is a highly inconvenient and painful procedure. Liquid biopsy cancer detection is a highly effective and painless affair.

There are multiple studies and research that are focusing on finding more uses for liquid biopsy in the field of medicine today. In an era where robotics surgery has seen such popularity, the day isn’t far when Liquid biopsy will find more use in the medical industry.

How does Liquid biopsy Work?

A liquid biopsy helps find and detect cancerous cells in the liquid sample collected from the patient.

As and when cancer grows within the body, the tumour grows. Small pieces of the tumour can eventually break off and flow into the patient’s bloodstream. Liquid biopsy test for cancer helps in detecting cancer from those pieces.

Liquid Biopsies can detect:

Circulating Tumor DNA (ctDNA)

This is a DNA fragment of the tumour cell circulating in the patient’s bloodstream. The DNA controls the genetic code or the instructions that control the behaviour of the Cell.

Circulating Tumor Cells (CTC)

This is a cancer cell from the tumour that is travelling within the patient’s bloodstream.


CTC & ctDNA are both evidence of cancerous cells in the patient’s body. The timely diagnosis also helps the doctors in deciding the right course of action for the patient.

How is a Liquid Biopsy Test Different from a Normal Biopsy?

Liquid biopsies are very different from the traditional needle biopsies we know of. Core needle biopsies and fine needle aspiration biopsies are the two primary types of biopsies that doctors around the world use to detect cancerous cells and treat them accordingly.

During needle or tissue biopsies the medical practitioner surgically removes a small amount of tissue from the tumour or the suspected area that is believed to be infected. Then this tissue or mass is further inspected by a pathologist who studies it under a microscope. They look for signs to find cancer in the collected matter.

Whereas Liquid Biopsies are done to support priorly done cancer diagnosis. These tests are done as an additional to understand the situation better and decide on the next course of action. They support the needle or tissue biopsies. These tests can be done multiple times throughout the procedure to understand what course of treatment is working effectively.

Understanding the Procedure and How It Works

Liquid biopsies are never usually the first choice of tests that are prescribed by medical practitioners. These are still under a lot of scrutiny and a lot of studies are being conducted right now to understand how to use them more proactively.

Liquid biopsy for cancer detection is a non-invasive procedure. The doctor collects blood samples from your blood veins as s/he would do before any other test. The patient doesn’t need to take special precautions before the sample collection. This sample is then sent to a laboratory for further detection. The results usually take about 7-10 days and then the results and next course of action are discussed with the doctor.

Advantages and Disadvantages

Liquid biopsies can be used as an alternative to understanding the journey of the tumour and its growth, along with more tests like needle biopsies. A liquid biopsy test for cancer comes into the picture when needle biopsies are not capable of collecting a tissue sample. Results from needle biopsies are known to be notoriously slow, so liquid biopsies become a saviour in case results are needed more quickly.

Sometimes it so happens that Liquid biopsies come negative for certain mutations, the patient might then have to do a follow-up test with a conventional biopsy specimen. A liquid biopsy test for cancer detection can miss out on details available from a conventional tissue biopsy and detect where a possible mutation has arisen.

Trends in Liquid Biopsy Test

The world is witnessing a surge of advancements in every field be it technology or healthcare. Medical AI, Geroscience & Robotics in healthcare were all a distant dream just a decade ago but things are showing drastic developments today. This is what the future of liquid biopsy looks like and here are the trends that will follow:

  • Non-Invasive prenatal testing: A small sample of blood is collected from the maternal plasma. They use this non-invasive procedure to predict if the fetus is to have any genetic abnormalities, by just studying the DNA that’s expelled into the bloodstream.
  • Mass population screening: Liquid biopsy tests can be used to detect diseases at a very early stage in large scales of the population and plan an effective course of action. Early mass screening helps in the reduction of infection and transmission.
  • RNA theaurapactics and Treatment Monitoring: Liquid biopsies have a future in the pharmaceutical industry. It can be used for treatment monitoring for cancer and other therapies for Duchenne Muscular Dystrophy.
  • Liquid Biopsy for skincare: Liquid biopsy not only contains cell circulating nucleic acid but also small circulating extracellular exosomes. These are carriers of MiRNA, mRNA and proteins. Exosomes are not only capable of cell-to-cell communication but also help in wound treatment and cosmetics.
  • Precision Oncology: This is a very patient-specific molecular profiling of tumour nucleic acids done for monitoring and treatment purposes.


Frequently Asked Questions for Liquid Biopsy for Cancer Tests

1. How much do Liquid Biopsy Tests Cost?

Liquid Biopsy tests can range from 25,000-2,50,000/- INR. The price will depend on the different markers screened and the laboratory tested in India.

2. Is the Procedure Painful?

Painlessness is one prominent liquid biopsy advantage. The doctor skillfully used a needle to collect a blood sample. That’s as much pain as one can imagine.

3. Can the Test Help in the Early Detection of Cancer?

Liquid biopsy tests for cancer detection can successfully detect certain types of cancer 4 years before the conventional diagnosis by using methylation markers.

4. Is the Test Accurate and Safe?

FDA-approved liquid biopsy tests are popular because they do what they claim on the surface. They predict accurately and are safe for the patient too.


Liquid biopsy can bring a major transformation and that day isn’t far. In this article, we have tried to cover all the basics regarding the topic of Liquid Biopsy. However, if you have further queries regarding the same, we would be happy to help.

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