From the Guidelines
The neutrophil to lymphocyte ratio (NLR) is a significant prognostic marker for poor outcomes in various conditions, including cancer, as it reflects the balance between systemic inflammation and immune response 1. The NLR is calculated by dividing the absolute neutrophil count by the absolute lymphocyte count from a complete blood count. A normal NLR typically ranges from 1 to 3, with values above 3 often considered elevated.
- Elevated NLR values are associated with reduced quality of life and survival in patients with advanced disease 1.
- The ratio serves as an inexpensive inflammatory marker that can help assess systemic inflammation and predict outcomes in various conditions.
- Neutrophils increase during acute inflammation while lymphocytes often decrease during physiological stress, making their ratio particularly sensitive to inflammatory states. Some key points to consider when interpreting NLR results include:
- Elevated neutrophil counts and low lymphocyte counts are associated with poor cancer outcomes 1.
- The NLR is part of a broader set of markers that predict poor outcomes, including altered acute phase proteins and symptoms such as fatigue, pain, and depression 1.
- Treating the underlying condition causing inflammation will typically normalize the ratio over time, rather than targeting the NLR directly with medications. It's essential to consider NLR results alongside other clinical findings and laboratory tests rather than in isolation to get a comprehensive understanding of a patient's condition.
From the Research
Significance of Neutrophil to Lymphocyte Ratio
The Neutrophil to Lymphocyte Ratio (NLR) is a significant marker of systemic inflammation that has been widely used to predict mortality and morbidity in various medical conditions. Some key points about NLR include:
- NLR is an easy-to-measure laboratory marker that reflects the dynamic relationship between innate and adaptive cellular immune responses during illness and various pathological states 2.
- An elevated NLR is associated with poor survival and increased morbidity in cancer and cardiovascular disease 3.
- NLR is influenced by many conditions, including age, chronic disease, medication, and stress 2.
- A normal range of NLR is between 1-2, while values higher than 3.0 and below 0.7 in adults are considered pathological 2.
Clinical Applications of NLR
NLR has various clinical applications, including:
- Predicting mortality in medical inpatients with multiple chronic conditions 3.
- Serving as a reliable and cheap marker of ongoing cancer-related inflammation and a valid indicator of prognosis of solid tumors 2.
- Diagnosing and stratifying systemic infection, sepsis, and bacteremia 2, 4.
- Predicting the outcome of patients with ST-elevation myocardial infarction (STEMI) 5.
- Identifying individuals at risk of mortality in the general population 6.
Interpretation of NLR Values
The interpretation of NLR values is crucial in clinical practice. Some key points include:
- NLR values above 3.0 are associated with increased mortality and morbidity in various medical conditions 3, 2, 5.
- NLR values in the grey zone between 2.3-3.0 may serve as an early warning of pathological states or processes 2.
- Dynamic changes in NLR values can precede clinical states and warn clinicians about ongoing pathological processes 2, 4.