The Value of the Neutrophil to Lymphocyte Ratio in the Diagnosis of Bacterial Infections

The "gold standard" for diagnosing a bacterial infection is isolation of the pathogenic germ, which is not easy in routine clinical practice.

Conventional markers do not have sufficient diagnostic value for making a rapid diagnosis on admission. A 2004 literature calculated the diagnostic values of C-reactive protein (CRP) and procalcitonin (PCT) levels for the diagnosis of bacterial infections, relative to other causes of inflammation. For CRP, the sensitivity was 75% (95% CI: 62%-84%) and the specificity was 67% (95% CI: 56%-77%). For PCT, the sensitivity was 88% (95% CI: 62%-84%) and the specificity was 81% (95% CI: 67%-90%).

The first cellular immune response to infection consists of the mobilization of polynuclear neutrophils from the bone marrow to the infection site under the effect of pre-inflammatory cytokines, as well as the apoptosis of lymphocytes and their sequestration at the infection site. This results in lymphopenia and the elevated polynuclear neutrophil count (PNN) observed in bacterial infections.

Hence, it is legitimate to hypothesize that the neutrophil to lymphocyte ratio (NLR) can be used in the diagnosis of bacterial infection. This ratio's value in the diagnosis of sepsis in the emergency department was studied and the researchers found higher diagnostic values than for CRP and PCT.

The NLR's potential value in the diagnosis of a bacterial infection in a context of fever or hyperthermia (regardless of the presence or absence of bacteraemia) has not been studied before. This ratio could also be compared with standard biomarkers (CRP and PCT levels, the white blood cell count and the PNN).

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Key information

Conditions

Bacterial Infections Bacterial Infections and Mycoses Body Temperature Changes Fever Heat Stress Disorders Hyperthermia Infections Pathological Conditions, Signs and Symptoms Signs and Symptoms Wounds and Injuries

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

CHU Amiens Picardie

Amiens, 80054, France

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

All consecutive patients admitted for fever/inflammatory syndrome to the internal medicine department at Amiens University Hospital between January 1 st 2011 and December 31 st 2014 (hyperthermia > 38°5 and/or inflammatory syndrome, defined as an increase in CRP >10 mg/L).

Exclusion criteria

Known conditions or treatments that may influence the blood count (haematological and neoplastic diseases, seropositivity for HIV, chemotherapy, and corticotherapy).
Pregnancy.
A course of antibiotics administered in the 48 hours before the
blood count (risk of sample negativity).

Treatment and study plan

neutrophil to lymphocyte ratio

Biological

value of the neutrophil to lymphocyte ratio in the diagnosis of bacterial infections

Primary outcomes

NLR / CRP

Time frame: 1 day

To compare the NLR with other commonly used inflammatory markers for the diagnosis of bacterial infection in patients admitted for fever and/or inflammatory syndrome to an internal medicine department.
NLR / PCT

Time frame: 1 day

To compare the NLR with other commonly used inflammatory markers for the diagnosis of bacterial infection in patients admitted for fever and/or inflammatory syndrome to an internal medicine department.
NLR / white blood cell count

Time frame: 1 day

To compare the NLR with other commonly used inflammatory markers for the diagnosis of bacterial infection in patients admitted for fever and/or inflammatory syndrome to an internal medicine department.
NLR / PNN

Time frame: 1 day

To compare the NLR with other commonly used inflammatory markers for the diagnosis of bacterial infection in patients admitted for fever and/or inflammatory syndrome to an internal medicine department.

Sponsors and collaborators

Lead sponsor

Centre Hospitalier Universitaire, Amiens

Other

Registry information

Acronym: RNL-MI

Important dates

Study start: 2016
Primary completion: 2016
Study completion: 2016
First posted: Jul 28, 2016
Registry last updated: Aug 10, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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