Excerpt
Neutrophil–lymphocyte and platelet–lymphocyte ratios are simple and easy to perform, which represents an interesting opportunity for them to be used as markers for various clinical conditions.
The change in the neutrophil–lymphocyte and platelet–lymphocyte ratios in otitis media with effusion has been studied in previous studies2 and the authors also concluded that the ratio could be used to predict the viscosity of the secretions. However, neutrophil-to-lymphocyte ratio varies with age and body mass index of the patients3 and therefore will vary from person to person. There are no cut-off values of neutrophil-to-lymphocyte ratio in healthy individuals to determine whether it is abnormal or not. Without such standardization it is difficult to determine the significance of neutrophil-to-lymphocyte ratio in these patients.
There are many other conditions such as Bells palsy4 and vestibular schwannoma,5 where the ratios can be deranged. Since the neutrophil-to-lymphocyte ratio can be influenced by so many common conditions, its specificity for using it as a diagnostic tool comes into doubt.
I would like to conclude by stating that neutrophil-to-lymphocyte ratio may be used as corroborative evidence and our understanding of the significance of neutrophil-to-lymphocyte ratio is far from adequate.