Yang (2020)
The diagnostic and predictive role of NLR, d-NLR and PLR in COVID-19 patients
Laboratory Findings
Derived NLR ratio (Abnormal vs. Normal)
COVID-19 (severe/critical)
Odds ratio: 1.901 (0.841-4.300) Adjusted model


Retrospective observational study

Medical records


The data from 93 laboratory-confirmed cases, to determine the effect of sex, age, CRP, WBC count, NLR, LMR, PLR, and co morbidities on the length of stay of patients with COVID-19 pneumonia.

The median age was 46.4 years old, and 37cases were females. A total of 26.8% of patients had been to Wuhan, and 73.1% had contacted with people from Wuhan. The average age was 58 years old, with 83 years old as the maximum. The average age of non-severe cases was 42 years old, with 7 months old as the minimum.


28 Day

COVID-19 (severe/critical)


Cases were diagnosed on the basis of the interim guidance of the World Health Organization (WHO) [5] and diagnosis and treatment guidelines of COVID-19 in China [8]. Non-severe patients met all following conditions: (1) Epidemiology history, (2) Fever or other respiratory symptoms, (3) Typical CT image abnormities of viral pneumonia, and (4) Positive result of RT-PCR for SARS-CoV-2 RNA. Severe patients additionally met at least one of the following conditions: (1) Shortness of breath, RR >= 30 times/min, (2) Oxygen saturation (Resting state) <= 93%, (3) PaO2/FiO2 <= 300 mmHg.

Laboratory Findings

Derived NLR ratio

d-NLR - derived neutrophil-to-lymphocyte ratio.



Odds ratio

1.901 (0.841-4.300)




age and gender, WBC, CRP, PLR, NLR and d-NLR

The COVID-19 epidemic may spread rapidly by human-to-human. The clinical manifestations of this disease can vary even in patients with the same viral infection; the severity of the condition may be related to the number of immune cells. Disease severity is an independent predictor of poor outcome. Age and NLR may be related to the severity of the infection and may also indicate the outcome of the condition.