Medical Oncologist
CION Cancer Clinics
How do you choose which genetic test to have? | CION Cancer Clinics
You choose it together with your genetic counsellor, once they have drawn your family tree. The test is matched to the cancers in your family and to who is being tested. If a relative's fault is already known, you are tested for that one change. This page explains the main options, how the choice is narrowed down, and what a broader or narrower test gains and loses. At CION Cancer Clinics in Hyderabad, our oncologists review your family history with you and guide you to the right genetic counselling and testing.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- How do you decide which genetic test to have?
- What kinds of test might be offered?
- How does the counsellor narrow it down?
- The words you will meet, in plain language
- A narrower test or a broader panel?
- What this page cannot tell you
- Four things families assume about choosing a test
- Common questions about choosing a genetic test
The short answer
How do you decide which genetic test to have?
You decide together with your genetic counsellor, after they have drawn your family tree. The test is matched to the pattern of cancer in your family and to who is being tested. If a fault is already known in a relative, the choice is simple: you are tested for that one change and nothing else.
What the choice depends on
Three things drive it. Which cancers appear in the family, and at what ages. Whether the person being tested already has cancer, because the result might change their treatment now. And how much uncertainty you are willing to live with, because broader tests find more changes nobody can yet explain.
Why you have a say
There is often more than one reasonable test. A counsellor will set out the options, what each might find and what each costs, and then ask what matters to you. Some people want the widest possible look. Others want only the answer that changes a decision this year. Both are fair choices.
This page covers tests for inherited faults, done on blood or saliva. Tests on the tumour itself are a separate question.The main options
What kinds of test might be offered?
Most families are offered one of the first three. The fourth is often confused with them, and answers a different question.
A known family fault
A relative has already tested positive. You are checked for that exact change only. It is the narrowest, clearest and cheapest test, and the answer is usually a plain yes or no.
One or two genes
Used when the family pattern points clearly at one syndrome, such as breast and ovarian cancer. Fewer genes means fewer uncertain results, but a fault in an unexpected gene can be missed.
A multigene panel
Many genes read at once, chosen to cover the cancers in your family. This is now the most common first test for the relative who has cancer.
Worth asking
- Which genes are on it, and why
- How uncertain results are reported
- Whether unrelated findings are included
A tumour test
Reads the faults inside the cancer to guide treatment. It is not designed to tell you what you inherited, and a hint of an inherited fault still needs a blood test to confirm it.
Not sure whether this applies to you?
Ask an oncologistIn the counselling room
How does the counsellor narrow it down?
Draw the family tree
Both sides of the family, who had which cancer and at roughly what age. Men and relatives who died young matter as much as anyone else.
Decide who is tested first
Wherever possible, the relative who already has or had cancer. Their result tells everyone else whether there is a fault to look for.
Match the test to the pattern
The counsellor picks the genes linked to the cancers in your family, and explains what a broader or narrower choice would add or lose.
Agree what you want to know
You decide how uncertain results and unrelated findings are handled, and you see the price, before you sign the consent form.
On the request form
The words you will meet, in plain language
- Single-site test
- A test for one known change already found in a relative. Also called a known-familial-variant test.
- Panel
- A group of genes read in one test. Panels differ in size between laboratories even when they share a name.
- Germline
- Present in every cell from birth, so it can be inherited. This is what a blood or saliva test looks for.
- Somatic
- Found only in the tumour, not inherited. Tumour tests look for these to guide treatment.
- VUS
- A variant of uncertain significance: a change the lab cannot yet call harmful or harmless. It should not change your care.
- Secondary finding
- A result in a gene unrelated to the reason for testing, reported only if you agreed to receive it.
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Side by side
A narrower test or a broader panel?
A narrower test
A broader panel
Fewer uncertain results to live with
More uncertain results, most of them harmless
May miss a fault in an unexpected gene
Can find faults outside the obvious pattern
Usually costs less
Usually costs more
Simpler to explain to relatives
May need longer counselling afterwards
Being straight with you
What this page cannot tell you
It cannot choose the test for you. The right test depends on details of your family that only come out when someone sits with you and draws the tree: an aunt diagnosed young, a grandfather with a rare cancer, a cousin marriage two generations back. Those details can change the answer completely.
It cannot tell you whether an old result is enough
If a relative was tested years ago, the test may have covered fewer genes than today's panels. Whether a newer test adds anything is a question for a counsellor who can see the old report.
Who this does not apply to
Most people with cancer in the family do not need a genetic test at all, and a counsellor may tell you that no test is the right choice. If you already have a result, what your specific variant means is a question for the counsellor who ordered the test. If your oncologist wants to know which medicine will work on the tumour, that is a tumour test, not this one.
Counselling can be held in Telugu, and by video if you live outside Hyderabad.Commonly believed
Four things families assume about choosing a test
"The biggest panel is always the best choice."
A bigger panel finds more changes nobody can yet explain, and those can cause worry without helping. The best test is the one that fits your family's pattern.
"The doctor chooses. We just give the sample."
You have a real say. A counsellor sets out the options, and you decide how much you want to know, including whether to receive unrelated findings at all.
"My sister tested negative, so I do not need a test."
It depends on what she was tested for. A negative result on a narrow test does not rule out faults in genes it did not read. Bring her report to your counsellor.
"The tumour test already told us whether it is inherited."
A tumour test is built to guide treatment. It can hint that a fault might be inherited, but only a blood or saliva test can confirm it.
Questions we are asked
Common questions about choosing a genetic test
Can I just ask for a BRCA test?
You can ask, and sometimes it is the right test. But other genes can cause a similar family pattern, and a counsellor may suggest a panel that includes them. Talk it through first so you do not pay for a test that misses the question you actually have.
Why test my mother first instead of me?
If she has had cancer, her result tells the family whether there is a fault to look for. If she tests negative, testing you usually adds little. If she tests positive, you can have the cheaper test for that one change.
What if the relative with cancer has died?
A stored tissue block from an old operation can sometimes be tested. If not, the counsellor may suggest testing you directly with a panel, while explaining that a negative result is less reassuring when the family fault is unknown.
Will a bigger panel find more uncertain results?
Yes. Every extra gene is another place a harmless or unexplained change can turn up. Uncertain results should not change your care, but they can worry families. Your counsellor will explain how they are handled before you choose.
Can I choose not to hear about unrelated findings?
Usually, yes. Many laboratories let you opt in or out of receiving findings in genes unrelated to your family's cancers. You make that choice on the consent form, and your counsellor will explain what it means before you sign.
Does the choice of test change the price?
Yes. A known-fault test costs much less than a panel, and panels vary in price between labs. Ask for the price of each option when the counsellor sets them out, so cost is part of the conversation rather than a surprise.
My relative was tested years ago. Should I test again?
Possibly. Older tests often read fewer genes, and some missed certain kinds of fault. A counsellor can look at the old report and tell you whether a newer test is likely to add anything for your family.
Who can help me choose?
A genetic counsellor or clinical geneticist, with your oncologist involved if you have cancer. If you are not sure where to start, call the CION helpline and someone will arrange a counselling appointment.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
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Sources
- National Cancer Institute — Genetic Testing for Inherited Cancer Susceptibility Syndromes
- MedlinePlus Genetics — What are the different types of genetic tests?
- NHS — Predictive genetic tests for cancer risk genes
- Cancer Research UK — Inherited cancer genes and increased cancer risk
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Pre-test counselling: what is coveredThe appointment where the test is chosenDrawing the pedigreeHow your family tree shapes the choiceDeciding whether you want secondary findings reportedThe choice you make on the consent formInformed consent for genetic testingWhat you agree to before the sample is taken
Talk to us
Not sure which test fits your family?
Tell us who in the family was diagnosed and at what age. We will arrange a counselling appointment where the options are set out plainly. One helpline serves every CION centre.