From the Guidelines
An elevated neutrophil-to-leukocyte ratio in blood by automated count typically indicates an active inflammatory or infectious process in the body, such as bacterial infection, inflammation, physical or emotional stress, or certain medications. This finding means that neutrophils, which are white blood cells that serve as the body's first line of defense against infections, make up a higher percentage of the total white blood cell count than normal. The normal range for neutrophils is typically 40-60% of total leukocytes in adults. When this percentage increases, it often suggests bacterial infection, inflammation, physical or emotional stress, certain medications (like corticosteroids), or sometimes more serious conditions like leukemia. Acute bacterial infections are the most common cause, as neutrophils are rapidly deployed to fight bacteria. Other causes include tissue damage from burns or heart attacks, inflammatory conditions like rheumatoid arthritis, and physiological stress from surgery or pregnancy. If you have an elevated neutrophil percentage, your healthcare provider will likely consider your symptoms and medical history to determine the underlying cause. Additional tests may be needed, and treatment will depend on addressing the specific cause rather than the neutrophil count itself, as supported by the most recent guidelines 1. It's essential to note that proper interpretation of this lab value requires medical expertise, and self-diagnosis should be avoided. Some key points to consider include:
- The diagnosis of spontaneous bacterial peritonitis (SBP) is based on neutrophil count in ascitic fluid of >250/mm3 1.
- Neutrophil count can be determined by microscopy or flow cytometry-based automated count 1.
- The use of reagent strips has no clear evidence to support it in routine practice 1. In real-life clinical practice, it is crucial to prioritize the patient's symptoms, medical history, and physical examination to determine the underlying cause of an elevated neutrophil-to-leukocyte ratio, rather than relying solely on this lab value. The most recent and highest quality study 1 provides the best guidance for managing patients with elevated neutrophil counts, emphasizing the importance of diagnostic paracentesis, neutrophil count, and antibiotic therapy in certain cases.
From the Research
Elevated Neutrophil-to-Leukocyte Ratio
An elevated neutrophil-to-leukocyte ratio (Neutrophil/100 White Blood Cells (WBC)) in blood by automated count may indicate:
- Systemic inflammation, disease progression, and poor prognosis 2
- Increased risk of cancer, cardiovascular disease, type 2 diabetes, and other age-related conditions 2
- Chronic systemic inflammation, which can be reflected by a high neutrophil count 3
- Activation of neutrophils, which can be indicated by elevated neutrophil functions such as superoxide production, nitroblue tetrazolium reduction activity, and phagocytosis 4
Possible Causes
Possible causes of an elevated neutrophil-to-leukocyte ratio include:
- Infection, trauma, inflammation, and certain diseases 2, 3
- Physical stress, emotional stress, and medications such as corticosteroids, lithium, and beta agonists 3
- Primary bone marrow disorders, such as acute leukemias, chronic leukemias, and myeloproliferative disorders 3
Clinical Significance
The clinical significance of an elevated neutrophil-to-leukocyte ratio can be indicated by:
- A normal range of Neutrophil-to-Lymphocyte Ratio (NLR) between 1-2, with values higher than 3.0 and below 0.7 in adults being pathological 5
- NLR values above 3.0 being associated with increased mortality, cancer-related inflammation, and poor prognosis 5
- Dynamic changes of NLR preceding the clinical state for several hours and warning clinicians about the ongoing pathological process early 5