The short answer
Any blood in what you cough up is worth a same-day call, even once. More than a few streaks belongs in an emergency department, and so does coughing blood with hard breathing, dizziness, fever or chest pain. A cough that will not go away, or gets worse, with hoarseness, weight loss or chest pain also needs reporting the same day. Sudden or severe chest pain needs 911.
Any blood in what you cough up is worth a call to your care team the same day.
Coughing up more than a few streaks of blood means going to an emergency department.
NCI says to check with your doctor about a cough that does not go away or gets worse over time. With hoarseness, weight loss or chest pain, report it the same day. Sudden or severe chest pain needs 911.
Shoulder or arm pain with hand weakness or a drooping eyelid, together with a cough, is a same-day concern.
On this page
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The whole article, with every detail and caution.
This page is for people with a cough that will not go away who wonder whether it could be lung cancer. It covers when to get help right away, the signs to report, the tests used, and lung cancer screening.
Get help now for these
MedlinePlus says to contact your provider any time you cough up blood. It says to get medical help right away if you cough up blood and have more than a few teaspoons of blood, chest pain, dizziness, lightheadedness, fever, blood in your urine or stools, or severe shortness of breath. This page sets the lines a little lower, to be cautious.
- Call 911 or go to an emergency department if you cough up more than a few streaks of blood. Do not drive yourself.
- Call 911 or go to an emergency department if you cough up blood and also have severe shortness of breath, chest pain, dizziness, lightheadedness or fever, or a very fast heartbeat. Do not drive yourself.
- Call 911 or go to an emergency department if breathing trouble comes on suddenly, or seriously interferes with breathing and talking, or if your lips or skin look blue or gray. Do not drive yourself.
- Call your care team the same day if you cough up a few small spots, flecks, or streaks of blood, or notice blood in your phlegm or on a tissue. Once is enough.
Do not drive yourself. Bring your medicine list.
A cough that will not go away
NCI says to check with your doctor if you have a cough that doesn't go away or gets worse over time. Most persistent coughs are not cancer, and only tests can tell. But do not wait to see if it passes.
NCI lists these other signs to check with your doctor about:
- chest discomfort or pain
- trouble breathing or wheezing
- blood in sputum (mucus coughed up from the lungs)
- hoarseness
- loss of appetite
- weight loss for no known reason
- fatigue
- trouble swallowing
- swelling in the face or the veins in the neck
Call your care team the same day if a cough that will not go away comes with any of these. Also call the same day for new shoulder or arm pain with hand weakness, or a drooping eyelid, together with a cough.
NCI says lung cancer sometimes causes no signs or symptoms. It may be found on a chest x-ray done for another reason. Signs may be caused by lung cancer or by other conditions.
A symptom is not a diagnosis covers how to hold uncertainty while tests are pending.
What actually gets checked
NCI's patient summary says lung cancer is usually diagnosed with tests that make pictures of the lung and the area around it. These include a chest x-ray and a CT scan. If lung cancer is suspected, you will have a biopsy.
For a fine-needle aspiration biopsy, a thin needle removes tissue or fluid from the lung. A CT scan, ultrasound or other imaging is used to find the abnormal spot. NCI says a chest x-ray is done afterward to make sure no air is leaking from the lung into the chest.
Ask your care team which test comes first in your case, and why.
Bring your medicines
Some medicines can cause a cough. Bring your full medicine list, including blood pressure pills, and ask whether any could be the cause. Do not stop a medicine on your own.
If you smoked, screening is a separate conversation
Screening is for people without symptoms. If you have a persistent cough, you need evaluation, not screening. But it is worth knowing whether you also qualify for screening once this is sorted out.
The US Preventive Services Task Force recommends annual low-dose CT for adults aged 50 to 80 who have a 20 pack-year smoking history and either currently smoke or quit within the past 15 years. It is a Grade B recommendation. A pack-year means smoking an average of one pack a day for one year. So two packs a day for ten years is 20 pack-years.
The Task Force says this changed its earlier advice, which used ages 55 to 80 and 30 pack-years. If you were told years ago that you did not qualify, the criteria have widened and you may qualify now.
Screening should stop once someone has not smoked for 15 years, or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery. Lung cancer screening covers what the scan involves.
What to bring to the appointment
- The date the cough started, as precisely as you can.
- Whether it is dry or productive, and if productive, the color, and whether you have seen any blood.
- What makes it worse.
- Every medicine, with doses.
- Smoking history in pack-years, and the year you quit if you did.
- Any workplace exposure to asbestos, silica, diesel exhaust, or radon.
- Whether you have already tried an inhaler, an antacid, or an antihistamine, and whether it helped.
Sources
Common questions
When is a long cough an emergency?
A long cough is usually not an emergency, but blood and sudden breathlessness change that. Call 911 or go to an emergency department if you cough up more than a few streaks of blood. Do the same if you cough up blood and also have severe shortness of breath, chest pain, dizziness, lightheadedness or fever. MedlinePlus says to get medical help right away for these. Also call 911 if breathing trouble comes on suddenly or seriously interferes with breathing and talking.
What if I only see a few flecks of blood?
Call your care team the same day, even if it has only happened once. Any blood in what you cough up is worth a same-day call.
Which other symptoms matter alongside a cough that will not go away?
NCI lists chest discomfort or pain, trouble breathing, wheezing, blood in sputum, hoarseness, loss of appetite, weight loss for no known reason, fatigue, trouble swallowing, and swelling in the face or neck veins. A cough that will not go away, or is getting worse, with any of these warrants a same-day call to your care team. Sudden or severe chest pain is different: call 911 or go to an emergency department, and do not drive yourself. Shoulder or arm pain with hand weakness or a drooping eyelid is also a reason for a same-day call.
How should I prepare before the appointment?
Keep a written record of dates, symptom severity, and how you respond to any medication. Write down your top questions in advance. Confirm the after-hours numbers for your care team, and connect with oncology social workers, financial navigators or support groups if you need them.
Questions to ask your doctor
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Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
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Written by: Cancer ExplainedSources last checked: 2026-07-23 what this meansLast updated: 2026-09-29Next planned review: 2027-08-03
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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