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You might have one or more tests to find out the cause of your symptoms. The tests you have depends on your symptoms. Usually, a cancer of unknown primary (CUP) is picked up on tests for something else.

If tests show you have cancer spread (secondary cancer), you usually have a number of further tests to try to find where the cancer started (the primary cancer).

We haven't listed all the tests you might have below. We have more information about tests to diagnose cancer and how you have them in our general cancer tests section.

Trying to find out where your cancer started

You have tests to try to find out where your cancer started (primary cancer).

CT scan

CT scans use x-rays to build up a picture of the inside of your body.

Ultrasound scan

An ultrasound scan can look for any abnormal areas in your tummy (abdomen) or pelvis. Find out how you have one.

Blood tests

Find out about the different types of blood tests you might have.


Find out about x-rays, including what they are and why you might have them.

Biopsy for cancer of unknown primary (CUP)

A biopsy means taking a sample of tissue so that it can be looked at under a microscope. This is the only way to be certain if an abnormal area is cancer or not.

PET-CT scan

Find out what a PET- CT scan is, how you have it and what happens after it.

MRI scan

Find out what an MRI scan is, how you have it and what happens afterwards.

Last reviewed: 
22 May 2020
Coronavirus and cancer

We know it’s a worrying time for people with cancer, we have information to help.

Read our information about coronavirus and cancer