Hematology, Oncology & Immunology · Topic 13 of 26

Neutropenic Fever

Oncology · infection emergency

Neutropenic Fever

Fever with an ANC under 500 is infection until proven otherwise: draw cultures, then give an antipseudomonal β-lactam within 60 minutes.

Key numbers

Fever 38.3 °C, ANC under 500ANC < 500/µL

Antipseudomonal β-lactam within 60 minutes≤ 60 min

High risk: MASCC < 21 or prolonged neutropeniaMASCC < 21

Continue antibiotics until ANC recovers above 500ANC ≥ 500

01 · Defined byFever 38.3 °C, ANC under 500

Neutropenic fever = a single oral temperature ≥ 38.3 °C (or ≥ 38.0 °C sustained over 1 hour) with an ANC < 500/µL, or an ANC expected to fall below 500 within 48 hours.

02 · GiveAntipseudomonal β-lactam within 60 minutes

Give the first dose of empiric antibiotics within 1 hour of triage: monotherapy with an antipseudomonal β-lactam — cefepime, piperacillin-tazobactam, or a carbapenem (meropenem or imipenem-cilastatin).

03 · The ruleAdd vancomycin only for set indications

Vancomycin is not part of the standard initial regimen. Add it for hemodynamic instability, radiographic pneumonia, skin or soft-tissue infection, suspected serious catheter infection, or gram-positive bacteria in a blood culture.

Causes & risk factors

Why it happens

High risk: MASCC < 21 or prolonged neutropeniaHigh risk = MASCC < 21, profound neutropenia (ANC ≤ 100) expected > 7 days, or comorbidity such as hypotension, new neurologic change, or a new infiltrate or hypoxemia — admit for IV antibiotics.

Presentation

What you'll see

Neutropenia mutes the signs of infectionBelow about 200 neutrophils/µL the inflammatory response is muted — leukocytosis, pyuria or pus at the infected site may be absent — so fever may be the only sign.

Diagnosis & monitoring

Work-up

ANC = WBC × (% neutrophils + bands)Absolute neutrophil count = total WBC × (% segmented neutrophils + % bands). Severity: mild 1000–1500, moderate 500–1000, severe < 500/µL; profound is < 100/µL.

Do right now

In this order

First moves

Fever 38.3 °C, ANC under 500ANC < 500/µL

→

Draw 2 blood culture sets, including every lumen

→

Antipseudomonal β-lactam within 60 minutes≤ 60 min

→

Add vancomycin only for set indications

Why each step

Fever 38.3 °C, ANC under 500Neutropenic fever = a single oral temperature ≥ 38.3 °C (or ≥ 38.0 °C sustained over 1 hour) with an ANC < 500/µL, or an ANC expected to fall below 500 within 48 hours.

Draw 2 blood culture sets, including every lumenObtain at least 2 sets of blood cultures before antibiotics — with a central line, one set from each lumen plus one peripheral; without one, 2 separate venipunctures — without delaying the first dose.

Antipseudomonal β-lactam within 60 minutesGive the first dose of empiric antibiotics within 1 hour of triage: monotherapy with an antipseudomonal β-lactam — cefepime, piperacillin-tazobactam, or a carbapenem (meropenem or imipenem-cilastatin).

Add vancomycin only for set indicationsVancomycin is not part of the standard initial regimen. Add it for hemodynamic instability, radiographic pneumonia, skin or soft-tissue infection, suspected serious catheter infection, or gram-positive bacteria in a blood culture.

Management

Orders

Low risk: oral fluoroquinolone plus amoxicillin-clavulanateSelected low-risk patients (MASCC ≥ 21) can go home on an oral fluoroquinolone plus amoxicillin-clavulanate (clindamycin if penicillin-allergic) after ≥ 4 hours of observation — not if they were already on fluoroquinolone prophylaxis.

Stop vancomycin at 2 days if no gram-positiveIf vancomycin was started and no gram-positive infection is found, it may be stopped after 2 days.

Persistent fever at 4–7 days: add antifungalIn high-risk patients with persistent or recurrent fever after 4–7 days of antibiotics and neutropenia expected to last > 7 days, start empiric antifungal therapy (or a preemptive strategy in stable patients).

Remove line for S. aureus, Pseudomonas, fungiA central line can usually stay with suspected bacteremia, but remove it for S. aureus, P. aeruginosa, fungal (Candida) or mycobacterial infection, Bacillus or Corynebacterium, or cultures that stay positive despite appropriate antibiotics.

The rules

Know these

Continue antibiotics until ANC recovers above 500Continue antibiotics at least through the neutropenia: for unexplained fever, until clear marrow recovery (ANC ≥ 500/µL); for a documented infection, until ANC ≥ 500 or longer if the infection needs it.

Low-risk or high-risk neutropenic fever?

Commonly confused

MASCC score	≥ 21
Neutropenia	Not profound or prolonged
Comorbidity	None significant
Setting	Outpatient after ≥ 4 hours of observation
Empiric antibiotics	Oral fluoroquinolone plus amoxicillin-clavulanate

More detail

Reference

Show 5 reference facts

Ceftazidime is no longer considered reliable empiric monotherapy at many centers; choose cefepime, piperacillin-tazobactam or a carbapenem instead.

Outpatients who are still febrile after 2–3 days of empiric antibiotics are re-evaluated and considered for admission.

Antibacterial and antifungal prophylaxis is recommended for patients expected to have profound, protracted neutropenia (< 100/µL for > 7 days).

Adjust antibiotics to culture susceptibilities; if a documented infection defervesces within 72 hours, treat for at least 7 days and, after chemotherapy, usually until the ANC exceeds 500/µL.

Antifungal choice (eg, fluconazole, an echinocandin such as caspofungin, voriconazole, posaconazole) depends on neutropenia severity and duration and prior fungal infection, and is best guided by infectious disease consultation.

Pearl

Without neutrophils there is little pus or infiltrate — fever may be the only sign of a lethal infection, so treat the fever.

Sources · Freifeld AG et al. Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the IDSA. Clin Infect Dis 2011;52(4):e56–e93 · Taplitz RA et al. Outpatient Management of Fever and Neutropenia in Adults Treated for Malignancy: ASCO and IDSA Clinical Practice Guideline Update. J Clin Oncol 2018;36:1443–1453 — abstract via Europe PMC · Merck Manual Professional — Neutropenia · Taplitz RA et al. Antimicrobial Prophylaxis for Adult Patients With Cancer-Related Immunosuppression: ASCO and IDSA Clinical Practice Guideline Update. J Clin Oncol 2018;36:3043–3054 — abstract via Europe PMC · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).