Routine blood parameters are helpful for early identification of influenza infection in children

Abstract

Background Routine blood parameters, such as the lymphocyte (LYM) count, platelet (PLT) count, lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), lymphocytes multiplied by platelets (LYM*PLT) and mean platelet volume-to-platelet ratio (MPV/PLT), are widely used to predict the prognosis of infectious diseases. We aimed to explore the value of these parameters in the early identification of influenza virus infection in children. Methods We conducted a single-center, retrospective, observational study of fever with influenza-like symptoms in pediatric outpatients from different age groups and evaluated the predictive value of various routine blood parameters measured within 48 h of the onset of fever for influenza virus infection. Results The LYM count, PLT count, LMR and LYM*PLT were lower, and the NLR and MPV/PLT were higher in children with an influenza infection (PCR-confirmed and symptomatic). The LYM count, LMR and LYM*PLT in the influenza infection group were lower in the 1- to 6-year-old subgroup, and the LMR and LYM*PLT in the influenza infection group were lower in the > 6-year-old subgroup. In the 1- to 6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.75, the sensitivity was 81.87%, the specificity was 84.31%, and the area under the curve (AUC) was 0.886; the cutoff value of the LMR for predicting influenza B virus infection was 3.71, the sensitivity was 73.58%, the specificity was 84.31%, and the AUC was 0.843. In the > 6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.05, the sensitivity was 89.27%, the specificity was 89.61%, and the AUC was 0.949; the cutoff value of the LMR for predicting influenza B virus infection was 2.88, the sensitivity was 83.19%, the specificity was 92.21%, and the AUC was 0.924. Conclusions Routine blood tests are simple, inexpensive and easy to perform, and they are useful for the early identification of influenza virus infection in children. The LMR had the strongest predictive value for influenza virus infection in children older than 1 year, particularly in children older than 6 years with influenza A virus infection.

Thrombocytopenia in Virus Infections

“…Pediatric outpatients with confirmed IAV or IBV infection showed slightly, though significantly, lower mean platelet counts compared to asymptomatic controls. Children with influenza-like illness who were IAV and IBV PCR negative had platelet counts in between the confirmed positive and healthy groups, and platelet counts could not reliably distinguish between influenza positive and negative children [ 188 ]. In adults, severe influenza infection is accompanied by an increased risk of pulmonary thromboembolisms and cardiovascular events (Sellers, 2017 #1) suggesting platelet activation occurs during infection.…”

Predictive significance of neutrophil‐to‐lymphocyte and platelet‐to‐lymphocyte for cytomegalovirus infection in infants less than 3 months: A retrospective study

“…NLR is also investigated as useful predictors for the viral infection. The NLR is sensitive for the detection of influenza virus infection 24 . Meanwhile, higher white blood cells, neutrophil, and NLR were found in COVID‐19 cases as compared to healthy controls 25 .…”

Clinical and Laboratory Findings in Children With Influenza Infections

“…In the study conducted by Fei et al [7] lymphocyte x platelet multiplier and MPV (Mean platelet volüme)/platelet ratios were found to be higher in children with influenza A infection compared to children with influenza symptoms but not influenza A. In the study of Zhu et al [1] lymphocyte, platelet count, lymphocyte/ monocyte ratio (LMR) and lymphocyte x platelet multiplier were lower, neutrophil/lymphocyte ratio (NLR) and MPV/ platelet ratio were higher in children with influenza infection compared to the control group. These results show that there is no difference in terms of inflammation between influenza A and B infections.…”

“…It causes infections in more than 1,000,000,000 people, serious illness in five million people, deaths of 250 to 500 thousand people each year. [1] It has been reported that influenza viruses infect 20-50% of children during the periods of pandemic. [2] It is estimated that the number of hospitalizations due to influenza in children under five years of age worldwide is more than 870,000 per year.…”