Can a kidney infection occur without leukocytosis (presence of leukocytes, white blood cells)?

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Last updated: May 5, 2025 • View editorial policy

From the Guidelines

It is possible to have a kidney infection without leukocytes in the urine, as indicated by the European Association of Urology guidelines, which state that pyelonephritis can present with or without symptoms of cystitis, including leukocytes 1. When diagnosing kidney infections, urinalysis is recommended, including assessment of white and red blood cells and nitrite 1. However, the absence of leukocytes does not rule out a kidney infection, as other indicators such as bacteria in urine, flank pain, fever, nausea, and vomiting can still be present. Some key points to consider in the diagnosis and treatment of kidney infections include:

  • Prompt differentiation between uncomplicated and potentially obstructive pyelonephritis is crucial, as the latter can swiftly progress to urosepsis 1.
  • Fluoroquinolones and cephalosporins are recommended for oral empiric treatment of uncomplicated pyelonephritis 1.
  • Patients with uncomplicated pyelonephritis requiring hospitalisation should be treated initially with an intravenous antimicrobial regimen 1. If kidney infection is suspected despite negative leukocyte results, additional testing such as urine culture, blood tests, or imaging studies may be necessary for diagnosis, as recommended by the European Association of Urology guidelines 1.

From the Research

Kidney Infection Without Leukocytes

  • The provided studies do not directly address the question of having a kidney infection without leukocytes 2, 3, 4, 5.
  • However, it can be inferred that the presence of leukocytes is often used as an indicator of infection, including kidney infections 2, 3.
  • The studies focus on the diagnosis, treatment, and prevention of urinary tract infections, including pyelonephritis, which is a type of kidney infection 2, 3, 4, 5.
  • They discuss the use of antibiotics, imaging, and other diagnostic tools to manage kidney infections, but do not specifically address the absence of leukocytes in these infections 2, 3, 4, 5.

Diagnosis and Treatment

  • Urine culture is recommended for the diagnosis and management of pyelonephritis, recurrent urinary tract infection, and complicated urinary tract infections 3.
  • Antibiotics targeted toward Escherichia coli, Proteus, Klebsiella, and Staphylococcus saprophyticus are the recommended treatment 3.
  • The duration of treatment varies by specific drug and type of infection, ranging from 3 to 5 days for uncomplicated cystitis to 7 to 14 days for pyelonephritis 3.

Antibiotic Therapy

  • Short-course antibiotic treatment is at least as effective as longer courses for both microbiological and clinical success in the treatment of acute uncomplicated pyelonephritis 4.
  • Oral antibiotics, including amoxicillin, amoxicillin-clavulanic acid, and cephalexin, have potential to be effective for a proportion of patients with pyelonephritis 5.
  • Ciprofloxacin may be effective at lower doses than currently prescribed 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Acute Pyelonephritis in Adults: Rapid Evidence Review.

American family physician, 2020

Research

A pharmacokinetic-pharmacodynamic assessment of oral antibiotics for pyelonephritis.

European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.