Neutrophil-to-Monocyte-Plus-Lymphocyte Ratio as a Potential Marker for Discriminating Pulmonary Tuberculosis From Nontuberculosis Infectious Lung Diseases

You La Jeon, MD, PhD; Woo-In Lee, MD, PhD; So Young Kang, MD, PhD; Myeong Hee Kim, MD, PhD


Lab Med. 2019;50(3):286-291. 

In This Article


Study Population

The distribution and demographic characteristics of the study population are presented in Table 1. Patients with non-TB infectious lung diseases included those with bacterial or viral pneumonia (n = 92), aspiration pneumonia (n = 47), or empyema (n = 20). The mean (SD) ages of patients with TB and non-TB infectious lung diseases were 52.4 (19.7) and 68.3 (16.5) years, respectively. The male-to-female sex ratios of both groups were similar.

Comparison of CBC Data Between TB and Non-TB Patient Groups

The original CBC parameters other than the monocyte count and all the modified CBC indices showed statistical differences between the 2 groups. The white blood cell (WBC) and neutrophil counts of patients in the TB group were significantly lower than those in the non-TB group. However, the lymphocyte and platelet (PLT) counts were significantly higher in the TB group. The modified CBC indices, such as the MLR, NLR, PLR, and NMLR with CRP, were statistically significantly lower in the TB group (Table 2).

Among the original CBC parameters and the modified CBC indices, the area under the curve (AUC) value was highest for the NMLR (AUC, 0.90 [95% confidence interval (CI), 0.86–0.93]) (Table 3). The NMLR also had a significantly higher AUC than those of the MLR (P <.001), NLR (P = .009), and PLR (P <.001) (Figure 1). An NMLR cut-off value of 3.95 had sensitivity and specificity of 90.0% and 78.6%, respectively, for differentiating TB and non-TB groups. The sensitivity and specificity of NLR was 83.6% and 78.6%, respectively (cut-off value, 6.4).

Figure 1.

The areas under the curves (AUC) for NLR and NMLR in discriminating TB from non-TB infectious lung diseases were 0.88 (95% confidence interval: 0.84–0.92) and 0.90 (0.86–0.93). NLR indicates neutrophil-to-lymphocyte ratio; NMLR, neutrophil-to-monocyte-plus-lymphocyte ratio.

The NMLR of healthy subjects was lower than that of patients with TB (mean [SD], 1.51 [0.82] and 2.71 [1.28], respectively; P <.001) (Figure 2). The AUC of the NMLR for differentiating patients with TB from healthy subjects was 0.85 (95% CI, 0.80–0.88). At a cut-off value of 1.77, the sensitivity and specificity were 79.1% and 82.7%, respectively. The CRP showed a higher AUC (0.83 [95% CI, 0.78–0.87]) than those of the original CBC parameters and modified CBC indices other than the NLR and NMLR.

Figure 2.

The distribution of NMLR of TB patients was slightly higher than that of healthy subjects and lower than that of non-TB patients. The bars indicate the mean value for each group. NMLR indicates neutrophil-to-monocyte-plus-lymphocyte ratio, TB, tuberculosis.