Complete blood count alterations due to the opioid use: what about the lymphocyte-related ratios, especially in monocyte to lymphocyte ratio and platelet to lymphocyte ratio?

This study was designed to compare the complete blood count values of opioid users (N = 61) and healthy subjects (N = 61), particularly monocyte-to-lymphocyte ratio (MLR) and platelet-to-lymphocyte ratio (PLR). PLR, MLR, and percentage of monocyte (MONO%) were significantly lower in opioid use disorder (OUD) group (P = 0.012, P = 0.005, P = 0.000). The area under the ROC curve of MLR and PLR levels for OUD was 0.349 and 0.368. MONO% correlated with substance use duration. Measurements like lymphocyte-related ratios and MONO% in opioid use can be important in substance monitoring, detection, and differentiation of acute and chronic conditions.