Chemotherapy tests

You have tests before and during your chemotherapy course. These help your doctor decide whether you are fit enough for treatment, and how well treatment is working.

Tests before treatment starts

Before your first treatment you’ll have tests to help your doctor decide what treatment you need. They can also compare the results with future tests to see how your treatment is working. 

Tests may include: 

  • blood tests
  • x-rays
  • scans
  • your height and weight
  • physical examination

Your doctor checks your height and weight as the dose of chemotherapy is based on your size (body mass index). 

Chemotherapy drugs can stop your bone marrow producing enough red blood cells, white blood cells and platelets. So before your treatment starts you need to have a blood test to check your levels of these. You may also have other blood tests, depending on your type of cancer.

You might also have some of the following tests, depending on your treatment:

Tests to check your lungs

Some chemotherapy drugs can affect the way your lungs work.

Your doctor will arrange for you to have a lung function test before you start taking any of these drugs. This measures how much air your lungs can hold and how well you're taking in oxygen.

Tests to check your heart

Some chemotherapy drugs can affect the muscles of the heart. This could change the rhythm of your heartbeat. In most people, this will go back to normal after you finish the chemotherapy.

If you’re going to have one of these drugs, you need to have your heart checked before you start treatment. 

You might also have a recording of the electrical activity of your heart. This test is called an electrocardiogram (ECG). An ECG tells your doctor how well your heart is working.

You might also have a heart ultrasound. This test is called an echocardiogram (or an ECHO). An ECHO checks the force that your heart is pumping with.

Both of these tests are painless.

Tests to check your liver

Some chemotherapy drugs can damage the liver, so you might have blood tests to check how well your liver is working.

The liver breaks down many drugs. So it needs to be working well to get rid of the chemotherapy.

Tests to check your kidneys

Some chemotherapy drugs can affect your kidneys. So you might have blood tests or need to collect your urine for testing.

The kidneys also get rid of the chemotherapy drugs when they've been broken down in the body, so they need to be working well.

One substance the blood tests look at is the amount of creatinine in the blood. Creatinine is a protein made by the muscles as they work. The muscle cells release creatinine into the bloodstream. It circulates in the blood round to the kidneys. The kidneys remove the creatinine and get rid of it in your urine.

The amount of creatinine your kidneys produce in the urine stays at about the same level and can be measured by a blood test. The blood test shows how fast the creatinine is being removed from the circulating blood. So it is a measure of how well your kidneys are working. If your kidney function begins to fall, the level of creatinine in the blood will rise and this will show up in your regular blood tests.

Some chemotherapy drugs can cause kidney damage. People having treatment with these drugs will have blood tests for creatinine before each course of chemotherapy. This is to make sure their kidneys are able to cope with the drugs.

Tests to check for viruses

Before treatment you might have blood tests to check for viruses such as hepatitis B, hepatitis C and HIV. Chemotherapy could weaken your immune system Open a glossary item so infections like this could worsen or become active again if you've had them in the past. You may have medicines to prevent or treat infection. 

Other tests

You could need other tests, depending on the type of chemotherapy you have and the side effects it may cause.

These may include:

  • a hearing test (audiogram), if the chemotherapy can affect hearing
  • more regular blood tests to check your clotting, if you're taking warfarin
  • more regular blood sugar tests, if you have diabetes and are taking steroids

Your doctor might also suggest you see your dentist, if there's time before you start treatment. Having any dental treatment while you’re having chemo can be more complicated. This is because there could be more risk of you getting an infection.

Sperm collection and storage

If you’re a man and the chemotherapy is likely to make you infertile, you might be able to bank sperm before your treatment begins.

Womens fertility and chemotherapy 

Some chemotherapy drugs are more likely than others to cause infertility in women. Infertility means you can’t get pregnant.

Whether your infertility is temporary or permanent depends partly on your drugs and doses. You can ask your doctors if the drugs you’re having are likely to make you infertile.

Tests when you go for your treatment

Blood tests

When you go to the hospital or clinic, the first thing you have each time is a blood test. In some centres you have this a day or two before your treatment.

It’s important that your chemotherapy nurse checks your red blood cell (RBC), white blood cell (WBC) and platelet count before you have your next treatment. If your RBC is too low, you may need a blood transfusion. If either your WBC or your platelet count is too low, having more treatment could push them down to a level that isn’t safe.  

You’ll also have blood tests to check how well your kidneys and liver are working. If they aren't working as well as they should, the chemotherapy may give you more side effects.

Some cancers produce chemicals (biomarkers) that can be found in the blood. Your doctor might take some blood to test for these markers. They can use it to see how well your treatment is working.

Waiting for results

After your blood has been taken, you’ll have to wait for the results to come back. If everything’s OK, you can go ahead with your treatment.

All chemotherapy drugs are prepared specially for each patient, so you may have to wait while the hospital pharmacy prepares your drugs. This can take a while, so you might want to take something with you to pass the time.

To reduce the amount of time you have to wait, often the blood tests can be taken a day or two before you’re due to have treatment. This could either be at the hospital or at your GP's surgery. Ask your chemo nurse about this, if you think it would make things easier for you. 

Your blood results

If your blood counts are too low, then unfortunately your treatment will have to be delayed. You’ll get another appointment to come back and have another blood test. This is usually about a week later. 

If the tests to check your liver and kidneys show that there have been changes in how well they’re working, you may need the dose of your treatment changed. Sometimes people may need a different treatment, but this is rare.

This page is due for review. We will update this as soon as possible.

  • Cancer and its Management (7th edition)
    J Tobias and D Hochhauser
    Wiley Blackwell 2015

  • Cancer Principle & Practice of Oncology (11th)
    V T DeVita Jr., T S Lawrence and S A Rosenberg
    Wolters Kluwer 2019

  • The Royal Marsden Hospital Manual of Clinical Nursing Procedures (10th edition)
    S Lister and others
    Wiley Blackwell 2020

Last reviewed: 
02 Jul 2020
Next review due: 
02 Jul 2023

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