Related Experiment Video

Updated: May 29, 2026

Evaluation of a Point-of-Care Testing Analyzer for Measuring Peripheral Blood Leukocytes
05:58

Evaluation of a Point-of-Care Testing Analyzer for Measuring Peripheral Blood Leukocytes

Published on: March 22, 2022

Diagnostic value of leukopenia in young febrile infants

Borja Gomez1, Santiago Mintegi, Edurne Lopez

  • 1Paediatric Emergency Department, Cruces Hospital, Barakaldo, Spain. borja.gomezcortes@osakidetza.net

The Pediatric Infectious Disease Journal
|September 28, 2011
PubMed

Insights

In febrile infants, low white blood cell count (leukopenia) is not a risk factor for serious bacterial infection (SBI). Well-appearing infants with leukopenia had a lower prevalence of SBI compared to those with normal counts.

Area of Science:

  • Pediatrics
  • Infectious Diseases
  • Hematology

Background:

  • Fever without a source in infants is common.
  • Identifying serious bacterial infection (SBI) is crucial.
  • The role of leukopenia in febrile infants requires clarification.

Purpose of the Study:

  • To evaluate the association between leukopenia and SBI in young febrile infants.
  • To determine if leukopenia is a risk factor for SBI in well-appearing infants.

Main Methods:

  • Retrospective registry-based study.
  • Inclusion of 1365 infants younger than 3 months with fever without a source.
  • Analysis of white blood cell counts and SBI prevalence in well-appearing infants aged 29-90 days.

Main Results:

  • Prevalence of SBI was 13.8% in infants with normal white blood cell counts.
  • Prevalence of SBI was 6.8% in infants with leukopenia (OR 0.45).
  • Prevalence of SBI was 36.6% in infants with leukocytosis (OR 3.59).
  • No SBI observed in febrile neonates with leukopenia.

Conclusions:

  • Leukopenia is not an independent risk factor for SBI in well-appearing febrile infants.
  • Leukopenia may indicate a lower risk of SBI in this population.
  • Clinical assessment remains paramount in managing febrile infants.

Related Concept Videos

Disorders of Leukocytes01:27

Disorders of Leukocytes

Leukocyte disorders can lead to either leukopenia, characterized by an abnormally low leukocyte count, or leukocytosis, marked by a very high leukocyte number.
Leukopenia may result from bone marrow disorders, autoimmune diseases, and infectious diseases. For example, conditions such as multiple myeloma and aplastic anemia can impair the bone marrow's ability to produce adequate leukocytes. Similarly, autoimmune diseases like lupus and viral infections such as HIV can prompt the immune system...
Pneumonia III: Complications and Assessment01:30

Pneumonia III: Complications and Assessment

Pneumonia poses the potential for numerous complications that warrant consideration. These complications include the following:
Structure and Function of Leukocytes01:21

Structure and Function of Leukocytes

An adult in good health typically has between 4,500 and 11,000 leukocytes, or white blood cells, per microliter of blood, which constitutes about 1% of the total blood volume. Unlike red blood cells, white blood cells contain a nucleus and other cellular organelles but do not have hemoglobin. Most white blood cells reside in connective tissues, particularly in lymphatic organs such as the lymph nodes, with only a small fraction present in circulating blood.
White blood cells protect the body...
Acute Pyelonephritis II: Diagnostic Studies and Management01:28

Acute Pyelonephritis II: Diagnostic Studies and Management

Introduction:For diagnosing acute pyelonephritis, a comprehensive patient history is collected to identify symptoms such as dysuria, frequent or urgent urination, flank pain, or costovertebral angle (CVA) tenderness that may suggest a kidney infection.Physical ExaminationDuring the physical examination, CVA tenderness is assessed. This involves gentle percussion over the costovertebral angle, where tenderness often indicates a kidney infection.Diagnostic TestsUrinalysis: Used to identify white...