# Situation: A nurse works in the pediatric emergency room and the pediatric oncology ward of a government hospital. A 4-year-old with acute lymphoblastic (lymphocytic) leukemia is on day 12 of induction chemotherapy. Her temperature is 38.4 °C on one reading. The complete blood count shows: White blood cells: 2,000/µL Segmented neutrophils: 12% Bands: 8% Lymphocytes: 75% Monocytes: 5% What is her absolute neutrophil count, and what should follow?

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> subject: Nursing Practice II — Maternal and Child Health Nursing

## 문제

Situation: A nurse works in the pediatric emergency room and the pediatric oncology ward of a government hospital.

A 4-year-old with acute lymphoblastic (lymphocytic) leukemia is on day 12 of induction chemotherapy. Her temperature is 38.4 °C on one reading. The complete blood count shows:
White blood cells: 2,000/µL
Segmented neutrophils: 12%
Bands: 8%
Lymphocytes: 75%
Monocytes: 5%
What is her absolute neutrophil count, and what should follow?

## 보기

1. 400/µL: recheck her temperature in 1 hour before acting
2. 1,500/µL: give paracetamol and keep observing her
3. 1,600/µL: repeat the blood count on the next morning
4. 400/µL: start intravenous antibiotics within 60 minutes **✔ 정답**

**정답: 4**

## 해설

Absolute neutrophil count = white cell count × (% segmented neutrophils + % bands) ÷ 100 = 2,000 × 20 ÷ 100 = 400/µL. A single temperature of 38.3 °C or higher with a count below 500/µL is febrile neutropenia, an emergency: cultures are obtained and broad-spectrum intravenous antibiotics are started within 60 minutes.

## 심화 해설

The first step is to calculate the absolute neutrophil count (ANC). The formula uses the total white blood cell (WBC) count and the combined percentage of segmented neutrophils and band neutrophils, because both are mature and immature forms of the neutrophil lineage that contribute to bacterial defense.

ANC = 2,000/µL × (12% + 8%) ÷ 100 = 2,000 × 20 ÷ 100 = 400/µL

This value falls below the critical threshold of 500/µL. When a patient with this degree of neutropenia develops a single temperature of 38.3 °C or higher, the condition is classified as febrile neutropenia. In a child receiving induction chemotherapy for acute lymphoblastic leukemia, this is an oncologic emergency because the immune system lacks sufficient neutrophils to contain even minor bacterial invasion. Fever may be the only early sign of a life-threatening bloodstream infection.

Febrile neutropenia requires immediate cultures and initiation of broad-spectrum intravenous antibiotics within 60 minutes of presentation. Delaying antibiotics to recheck the temperature, observe the patient, or wait for repeat laboratory results increases the risk of rapid clinical deterioration and sepsis-related mortality.

The lymphocyte percentage of 75% is elevated relative to neutrophils, but lymphocytes are not included in the ANC calculation because they do not function as phagocytes against bacterial pathogens in the same way neutrophils do. The monocyte count of 5% is also excluded from the ANC formula, although monocytes do contribute to the broader absolute phagocyte count (APC), which some centers use as an adjunct marker for bone marrow recovery or safe antibiotic discontinuation.

| Parameter | Value | Role in febrile neutropenia |
| --- | --- | --- |
| Total WBC | 2,000/µL | Used as the base for ANC calculation |
| Segmented neutrophils | 12% | Mature neutrophils; included in ANC |
| Bands | 8% | Immature neutrophils; included in ANC |
| ANC | 400/µL | Severe neutropenia; defines high-risk febrile neutropenia |
| Lymphocytes | 75% | Not included in ANC; relative lymphocytosis from neutropenia |
| Monocytes | 5% | Not included in ANC; part of APC in some protocols |

Key point! A single temperature of 38.3 °C or higher in a neutropenic oncology patient is sufficient to trigger the febrile neutropenia pathway. Do not wait for a second reading or for the fever to persist.

Watch out! The ANC is not the same as the total WBC count. A WBC of 2,000/µL may appear only mildly low, but when neutrophils make up only 20% of that total, the functional antibacterial defense is severely compromised.

The rationale for immediate antibiotic administration is supported by the understanding that empirical broad-spectrum therapy must begin before culture results return. In pediatric oncology, the traditional approach has been to continue antibiotics until fever resolves and the ANC recovers to at least 500/µL [1][2]. However, recent studies in children with high-risk febrile neutropenia have explored early discontinuation of empirical antibiotics in clinically stable patients who remain afebrile for 72 hours or longer, even before full ANC recovery [2]. These studies do not change the initial emergency management; they address the later question of when antibiotics can be safely stopped after the patient has stabilized.

Some centers have also investigated whether the absolute phagocyte count, which adds monocytes and bands to the ANC, can serve as an earlier or safer marker of bone marrow recovery than ANC alone [3][4]. For example, one pilot study used discharge criteria of ANC ≥100/µL plus APC ≥300/µL instead of the traditional ANC ≥500/µL, with no increase in readmissions or deaths [3]. Another study suggested that the absolute monocyte count may be an earlier marker for safe antibiotic cessation in children with unexplained febrile neutropenia [4]. These findings are relevant to discharge planning and antibiotic stewardship, but they do not alter the acute presentation management.

At the moment a febrile neutropenic child presents to the emergency department, the priority is obtaining blood cultures and administering broad-spectrum intravenous antibiotics within 60 minutes, not waiting for additional temperature readings or repeat blood counts. The ANC of 400/µL places this patient in the high-risk category, and any delay in antibiotic initiation increases the risk of overwhelming sepsis.References (research sources)

- [1]EARLY DISCONTINUATION OF ANTIBIOTICS IN PEDIATRIC PATIENTS WITH LOW- AND HIGH-RISK FEBRILE NEUTROPENIA: A SINGLE-CENTRE EXPERIENCE.Research articleCosta CC, Puiggene AB, Malagarriga NM, Ruiz-Cobo MA, Martinez-de-Albeniz I, Bersch JG, Noguera-Julian A, Nebot SS. (2026) · DOI: 10.1093/jpids/piag094

- [2]Cost-Effectiveness of Early Empirical Antibiotic Cessation in Pediatric High-Risk Febrile Neutropenia.Research articleGiri RK, Sra MS, Kumar Kn S, Sasi A, Pushpam D, Batra A, Choudhary AH, Satpathy S, Haldar P, Vishnubhatla S, Ganguly S, Bakhshi S. (2026) · DOI: 10.1002/1545-5017.70703

- [3]Incorporating Absolute Phagocyte Count With Absolute Neutrophil Count as a Measure for Safe Discharge for Pediatric Oncology Febrile Neutropenia: A Pilot Study.Research articlePicca A, Wahlquist AE, Hudspeth M (2021) · DOI: 10.1097/MPH.0000000000001974

- [4]Absolute Monocyte Count as Early and Safe Marker for Antibiotic Cessation in Febrile Neutropenia Without Etiology in Pediatric Oncology Patients.Research articleAlali M, Prather C, Danziger-Isakov LA, Kussin ML, Khalifeh M, Al Othman N (2023) · DOI: 10.1097/MPH.0000000000002696

## 임상 시나리오

Febrile Neutropenia in Pediatric OncologyImmediate action for fever with low ANC
Calculate absolute neutrophil count as WBC × (segs + bands) ÷ 100. A value below 500/µL with a single temperature of 38.3 °C or higher defines febrile neutropenia.

Obtain blood cultures and start broad-spectrum IV antibiotics within 60 minutes of presentation. Fever may be the only sign of life-threatening bacteremia in a neutropenic child.

CautionDo not delay antibiotics to recheck temperature, observe, or await repeat labs. Each hour of delay increases sepsis-related mortality in induction chemotherapy patients.

## 핵심 개념

- **Absolute neutrophil count** — Total WBC multiplied by the sum of segmented neutrophils and bands, reflecting available bacterial defense.
- **Febrile neutropenia** — Single temperature 38.3 °C or higher with ANC below 500/µL, an oncologic emergency requiring immediate antibiotics.
- **Induction chemotherapy** — Initial intensive phase of leukemia treatment that causes profound bone marrow suppression and neutropenia.
- **Band neutrophils** — Immature neutrophils included with segmented neutrophils when calculating ANC.
- **Broad-spectrum antibiotics** — Empiric intravenous agents started within 60 minutes for febrile neutropenia before culture results return.

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