Neutrophil Lymphocyte Ratio (NLR) Calculator

Neutrophil Lymphocyte Ratio Explained

Under physiological stress, the number of neutrophils tends to increase whilst the number of lymphocytes decreases. NLR is able to quantify in a simple to compute ratio these changes and correlate them to the severity of physiological stress.

The mechanism is linked to the action of endogenous cortisol and catecholamines, perhaps also that of cytokines, endogenous catecholamines and other hormones.

Formulas

• NLR = Absolute Neutrophil Count (ANC) / Absolute Lymphocyte Count (ALC)
• NLR = Relative Neutrophil % / Relative Lymphocyte %

The correlation between NLR and physiological stress levels

NLR can act as a red flag alerting of a dysregulated immune system, whether from inflammation, malignancy or other causes. Critically ill patients will often have an NLR of 9 or higher. NLR tends to increase rapidly following acute physiologic stress (<6 hours).​

In a study by Biyik et al. on patients with liver cirrhosis, it was found that NLR of at least 2.72 had a significantly lower survival.

In a study by Templeton et al. on data from 100 studies (totalling 40,559 cancer patients’ data), a NLR greater than 4 was associated with statistically poorer survival in all disease subgroups, sites, and stages.

Whilst the NLR was found to perform better than standard white blood cell count in determining physiological stress, it has not proven to have any differentiating properties, for example differentiating haemorrhagic shock from septic shock.

Limitations of the NLR include a direct increase if the patient is under exogenous steroid therapy, or if the patient suffers from an active haematological disorder that affects cell count.

References

Original Reference

Zahorec R. Ratio of neutrophil to lymphocyte counts–rapid and simple parameter of systemic inflammation and stress in critically ill. Bratisl Lek Listy. 2001; 102(1):5-14.

Other references

Biyik M, Ucar R, Solak Y, Gungor G, Polat I, Gaipov A, Cakir OO, Ataseven H, Demir A, Turk S, Polat H. Blood neutrophil-to-lymphocyte ratio independently predicts survival in patients with liver cirrhosis. Eur J Gastroenterol Hepatol. 2013; 25(4):435-41.

Forget P, Khalifa C, Defour JP, Latinne D, Van Pel MC, De Kock M. What is the normal value of the neutrophil-to-lymphocyte ratio? BMC Res Notes. 2017; 10(1):12.

Templeton AJ, McNamara MG, Šeruga B, et al. Prognostic role of neutrophil-to-lymphocyte ratio in solid tumors: a systematic review and meta-analysis. J Natl Cancer Inst. 2014; 106(6):dju124.

Park JM. Neutrophil-to-lymphocyte ratio in trauma patients. J Trauma Acute Care Surg. 2017; 82(1):225-226.