The short answer
A central line infection happens when germs get into the catheter that runs into a large vein near the heart. MedlinePlus says to report redness or red streaks, swelling or warmth, yellow or green drainage, and pain. A fever of 100.4 °F (38 °C) or higher after a transplant is an emergency, so call at once, at any hour. Never touch the line without washing your hands first.
Redness at the site or red streaks spreading from it is a reportable sign.
Swelling, warmth, pain or yellow or green drainage all need a call.
A fever counts even when the site looks perfectly normal, and after a transplant it is an emergency call, not a same-day one.
MedlinePlus says not to touch your central line unless you have washed your hands.
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The full explanation.
When to get help sooner
Call 911 if you become very unwell very quickly — shaking chills with a high temperature, confusion, or a sudden inability to stay awake or breathe comfortably. A germ that reaches a central line has direct access to the bloodstream, so rapid deterioration is treated as an emergency, not as something to sleep on.
Call your care team immediately, at any hour, for a temperature of 100.4 °F (38 °C) or higher. That is the figure CDC gives for infection during cancer treatment, and after a transplant your marrow cannot mount a defence, so a fever is a medical emergency rather than a message left for the morning. If nobody answers within a few minutes, go to an emergency department and tell them at once that you have had a transplant and have a central line. Do not take anything to bring the temperature down before you speak to your doctor — CDC warns that this can mask a serious problem.
Call your care team the same day for the other signs MedlinePlus lists: redness at the site or red streaks around it, swelling or warmth at the site, yellow or green drainage, and pain or discomfort. Call the same day too if the line gets dirty, appears to be coming out of the vein, is leaking, or if the catheter is cut or cracked.
Why this particular tube deserves attention
MedlinePlus explains a central line simply. It is a catheter placed in a vein that leads to the heart or nearby large vessels, and an infection happens when bacteria contaminate that tube.
That description contains the whole reason for the fuss. A scratch on your arm has to work hard to cause serious illness. A germ on a line hub does not — it has a short, direct route inward. This is why hospitals treat central line care as a precise procedure rather than a casual one.
The line is helping you. It is also a door into your bloodstream, so it gets watched.
The daily check
Looking at the site once a day, in good light, is enough for most people. You are comparing today against yesterday.
- Is the skin around the site the same colour, or is there new redness?
- Are there red streaks running away from the site?
- Is the area puffier or warmer than it was?
- Is anything leaking, particularly yellow or green fluid?
- Does it hurt or feel uncomfortable when it did not before?
MedlinePlus's prevention advice for patients is short. Do not touch your central line unless you have washed your hands. Dressings, whether gauze or tape, should be changed if they are dirty. In hospital, staff check the line every day to confirm it is in the right place and to look for signs of infection — at home, that job falls to you and whoever helps you.
Fever without a visible problem
It is possible for a line infection to declare itself as a fever with a completely normal-looking site. MedlinePlus includes fever in its list of central line infection signs precisely because it can arrive on its own.
NCI's infection page describes other signals worth knowing during cancer treatment: chills, cough, sore throat, diarrhoea, ear, head or sinus pain, a stiff neck, skin rash, mouth sores, swelling at catheter sites, and changes in urine. It states that infections during cancer treatment can be life threatening and require urgent medical attention.
So a temperature is a reason to ring in straight away, whatever the clock says, and not a reason to wait and see whether the site catches up.
Keeping it simple
If you take one habit away from this page, make it hand washing before any contact with the line or dressing. If you take a second, make it the daily look. Between them they catch most of what a person can catch at home, and everything else is a phone call to a team that would far rather hear from you early.
Words to know
Tap any term to see what it means.
Common questions
What is a central line?
MedlinePlus describes it as a catheter, a tube placed in a vein that leads to the heart or nearby large vessels. An infection occurs when bacteria contaminate that tube.
Which signs should I be looking at every day?
MedlinePlus lists redness at the site or red streaks around it, swelling or warmth at the site, yellow or green drainage, pain or discomfort, and fever.
Does the line itself need reporting for anything other than infection?
Yes. MedlinePlus says to contact your nurse or provider right away if the line gets dirty, is coming out of your vein, or is leaking, or if the catheter is cut or cracked.
What is the single most useful thing I can do?
Hand hygiene. MedlinePlus puts it directly: make sure not to touch your central line unless you have washed your hands.
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Sources last checked: 2026-08-11 what this meansLast updated: 2026-08-20Next planned review: 2027-08-11
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How this page was created
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. We do not employ clinicians and do not intend to — our work 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 checked line by line against the sources listed on it. That confirms the sources support what the page says. 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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