The short answer
Doctors use lab tests, imaging, and biopsies to diagnose and monitor cancer. Before a test or scan, it helps to ask why it's needed, how to prepare, whether contrast dye is involved, and when and how you'll get the results. Useful questions also cover who will explain the findings and whether repeat testing will be needed. Bring the ones that fit your situation.
Ask why a specific test or scan is needed and what your care team is looking for.
Ask how to prepare — including eating, drinking, and medicines — before the appointment.
Ask whether you'll receive contrast dye and how long the test will take.
Ask when and how you'll get results, and who will explain them to you.
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The full explanation.
Why these questions matter
Doctors use a mix of lab tests, imaging, and biopsy to diagnose and monitor cancer. Blood chemistry tests, complete blood counts, tumor markers, urinalysis, and liquid biopsies are common lab tests; CT, MRI, PET and other nuclear scans, bone scans, ultrasound, and x-ray are common imaging tests. Knowing what to ask before any of these can make the process less confusing.
These prompts are adapted from facts the National Cancer Institute provides about diagnostic testing.
The essentials
- Why do I need this test or scan, and what are you looking for?
- How long will the test take?
About preparing
- How should I prepare — eating, drinking, or medicines?
- Will I get contrast dye?
Some imaging tests use a contrast dye to make certain tissues show up more clearly. It's worth asking ahead of time, since preparation can differ depending on whether dye is used.
About the results
- When and how will I get the results?
- Who will explain the results to me?
- Will I need repeat tests to monitor treatment?
Results often appear in a patient portal as soon as they're finalized, sometimes before your doctor has reviewed them with you. Normal ranges vary from person to person, and even day to day for the same person, so a single result — especially one you're reading without context — can be more confusing than clarifying. A single test alone typically can't confirm cancer; doctors usually combine several kinds of information.
Make it yours
Depending on the type of test, it can help to also ask:
- Whether you'll need someone to drive you home afterward.
- Whether the test involves any discomfort, and how long any effects might last.
- What happens if the first test isn't conclusive.
The takeaway
Tests and scans can feel like a waiting game, but a few upfront questions about purpose, preparation, and timing can make the process feel less like a black box. Ask what your care team is looking for, how to prepare, and when and how you'll learn what they find.
Words to know
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Common questions
▸Why did my test results show up in my patient portal before my doctor called?
Results often become available in a patient portal as soon as they're finalized, which can be before your doctor has had a chance to review and discuss them with you. It's reasonable to wait for that conversation, since normal ranges vary and a single result rarely tells the whole story.
▸Can one test alone diagnose cancer?
Usually not. Doctors typically combine information from lab tests, imaging, and biopsy results, since normal ranges can vary from person to person and even day to day for the same person.
▸How many questions should I bring before a test or scan?
As many as help you feel prepared. Basic logistics questions — like how to prepare and when to expect results — are often the most useful to ask ahead of time.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
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Your next step
Pick the questions that fit your situation, then print or save them.
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