The Value of the Neutrophil to Lymphocyte Ratio in the Diagnosis of Bacterial Infections (RNL-MI)

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).

Study Overview

• Status: Completed
• Conditions: Bacterial Infections
• Intervention / Treatment: Biological: neutrophil to lymphocyte ratio

• Study Type: Observational
• Enrollment (Actual): 479

Contacts and Locations

Study Locations

• France
  • Amiens, France, 80054
    • CHU Amiens Picardie

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

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).

Description

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).

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
NLR / CRP	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.	1 day
NLR / PCT	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.	1 day
NLR / white blood cell count	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.	1 day
NLR / PNN	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.	1 day

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire, Amiens

Study record dates

Study Major Dates

• Study Start (ACTUAL): February 6, 2016
• Primary Completion (ACTUAL): September 12, 2016
• Study Completion (ACTUAL): September 12, 2016

Study Registration Dates

• First Submitted: July 26, 2016
• First Submitted That Met QC Criteria: July 26, 2016
• First Posted (ESTIMATE): July 28, 2016

Study Record Updates

• Last Update Posted (ACTUAL): August 10, 2018
• Last Update Submitted That Met QC Criteria: August 9, 2018
• Last Verified: August 1, 2018

More Information

Terms related to this study

• Keywords: fever; hyperthermia; inflammatory syndrome
• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Bacterial Infections and Mycoses; Infections; Communicable Diseases; Bacterial Infections
• Other Study ID Numbers: RNI2015-40 Schmidt-2