The short answer
Clear, evidence-backed information helps patients, families, and caregivers make confident, informed medical and life decisions.
Every individual's cancer journey requires clear communication and personalized clinical support.
Empowered navigation reduces stress during diagnostics, treatment, and caregiving transitions.
Relying on established healthcare guidelines protects physical and emotional well-being.
Choose how you want to understand this
The full explanation.
Neutropenia & Low White Blood Cell Counts Guide
Neutrophils are the white blood cells that do most of the work of fighting infection. The National Cancer Institute defines neutropenia as "a condition in which there is a low number of neutrophils." Chemotherapy and some cancers lower that number, and while it is low, your body cannot mount its usual defence.
The one thing to memorise
[!WARNING] NCI lists a "fever of 100.5 °F (38 °C) or higher" as a sign of infection.
NCI states: "Call your health care team if you have signs of an infection. Infections during cancer treatment can be life threatening and require urgent medical attention."
Read that as written. Not 100 degrees, not "about 101," not "if it stays up." 100.5 °F (38 °C) or higher.
And urgent means urgent. If your temperature reaches that number at 2 a.m. on a Sunday, you call then — not when the clinic opens on Monday. Your oncology team has an after-hours number for exactly this reason. This is one of the few things in cancer care that cannot wait for business hours. Ask your team now, before you need it, which signs mean calling them and which mean going straight to the emergency room.
Do not take anything for the fever first
This is the step people get wrong out of good intentions. NCI warns: "Be sure to talk with your doctor or nurse before taking medicine—even aspirin, acetaminophen (such as Tylenol®), or ibuprofen (such as Advil®) for a fever. These medicines can lower a fever but may also mask or hide signs of a more serious problem."
Bringing the number down does not treat the infection. It hides the signal your team needs.
Other signs of infection to report
Alongside fever, NCI lists:
- chills
- cough or sore throat
- diarrhea
- ear pain, headache or sinus pain, or a stiff or sore neck
- skin rash
- sores or white coating in your mouth or on your tongue
- swelling or redness, especially where a catheter enters your body
- urine that is bloody or cloudy, or pain when you urinate
The American Cancer Society adds fast heartbeat, breathing problems, dizziness or lightheadedness, and joint or bone pain, and says to "talk with your cancer care team right away if you have any signs or symptoms of an infection."
An important caveat: with very few neutrophils, your body may not produce the usual redness, swelling, or pus. Fever can be the only sign you get.
Why your counts drop, and when
NCI explains that some cancers and treatments such as chemotherapy raise infection risk because they lower white blood cell numbers: "During chemotherapy, there will be times in your treatment cycle when the number of white blood cells (called neutrophils) is particularly low and you are at increased risk of infection." NCI adds that stress, poor nutrition, and not enough sleep can also weaken the immune system.
Ask your team when in your cycle your count is expected to be lowest — that is the window to be most careful in.
NCI notes that "medicine may sometimes be given to help prevent infection or to increase the number of white blood cells." ACS describes these as growth factors, "also called granulocyte colony-stimulating factors (G-CSFs)," usually given as a shot.
Lowering your risk day to day
NCI's prevention advice:
Wash your hands often and well. Use soap and warm water, especially before eating. Have people around you wash their hands well too.
Stay extra clean. If you have a catheter, keep the area around it clean and dry. Clean your teeth well and check your mouth for sores each day. Clean any scrape or cut well. Tell your doctor or nurse if your bottom is sore or bleeds, as this could increase your risk of infection.
Avoid germs. Stay away from people who are sick or have a cold. Avoid crowds, and people who have just had a live vaccine such as one for chicken pox, polio, or measles.
Handle food safely. Make sure meat, fish, and eggs are well cooked. You may be advised to eat only fruits and vegetables that can be peeled, or to wash all raw fruits and vegetables very well.
Questions for your team
NCI suggests bringing these to your visit:
- Am I at increased risk of infection during treatment? When am I at increased risk?
- What steps should I take to prevent infection?
- What signs of infection should I look for?
- Which signs signal that I need urgent medical care at the emergency room? Which should I call you about?
Sources
- National Cancer Institute: Infection and Neutropenia during Cancer Treatment. https://www.cancer.gov/about-cancer/treatment/side-effects/infection
- American Cancer Society: What to Do for Low White Blood Cell Counts. https://www.cancer.org/content/dam/cancer-org/cancer-control/en/what-to-do/what-to-do-for-low-white-blood-cell-counts.pdf
- American Cancer Society: Low White Blood Cell Counts (Neutropenia). https://www.cancer.org/cancer/managing-cancer/side-effects/low-blood-counts/neutropenia.html
<script type="application/ld+json"> { "@context": "https://schema.org", "@type": "MedicalWebPage", "headline": "Neutropenia & Low White Blood Cell Counts Guide", "description": "What neutropenia is, the exact fever threshold that means calling your team urgently, and how to lower your infection risk.", "url": "https://cancerexplained.org/side-effects/neutropenia-and-low-white-blood-cell-counts", "datePublished": "2026-07-23", "dateModified": "2026-07-28", "publisher": { "@type": "Organization", "name": "Cancer Explained", "url": "https://cancerexplained.org" }, "author": { "@type": "Organization", "name": "Cancer Explained Editorial Team" }, "medicalAudience": "Patient", "aspect": "Cancer Navigation and Support" } </script>
Words to know
Tap any term to see what it means.
Common questions
What is the best way to handle complex healthcare navigation?
Keep organized written records, utilize patient advocates or social workers, and prepare a written list of questions before appointments.
Where can I find verified guidance for cancer treatment and support?
Rely on reputable organizations like the National Cancer Institute (NCI), ASCO's Cancer.net, and CancerExplained.org.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Speak With Trained Specialists & Human Navigators
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Immediate emergency guidance for fever (>100.4°F during chemo), severe pain, or shortness of breath.
Help Us Improve This Guide
Did this explanation answer your question and help you determine your next step?
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
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 verified — This page was created with AI assistance and checked against the sources listed on it. Source checking is not a medical review.
Human medical review: not completed. Cancer Explained is not clinician-reviewed, and that is a deliberate design choice rather than a gap we are waiting to close. We restate published federal guidance and cite it; the authority belongs to the source, not to us. That is why every page names where its claims come from — so you can verify us instead of trusting us. Use it to understand your situation and to ask better questions of the people treating you.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
Related articles
Still have questions?
Educational answers, plain language