General
NLR may be calculated using either absolute cell counts or percentages, as shown here:
Interpretation of NLR:
- A normal NLR is roughly 1-3.
- An NLR of 6-9 suggests mild stress (e.g. a patient with uncomplicated appendicitis).
- Critically ill patients will often have an NLR of ~9 or higher (occasionally reaching values close to 100).
Clinical Use
Pitfalls
- Exogenous steroid: May directly increase the NLR.
- Active hematologic disorder: Leukemia, cytotoxic chemotherapy, or granulocyte colony stimulating factor (G-CSF) may affect cell counts.
- HIV: Some studies have excluded patients with HIV. Overall the utility of NLR in this patient population remains unclear. Patients with advanced AIDS and chronic lymphopenia might be expected to have a higher baseline NLR.