
Objectives: This study aimed to evaluate the usefulness of several hematological parameters in the diagnosis of acute pyelonephritis and cystitis, as well as in differentiating between these two diseases. Materials and Methods: The patients were divided into two groups: those treated for acute pyelonephritis (APN) and those treated for cystitis. Complete blood counts were obtained from all the patients, including the mean platelet volume (MPV), platelet/lymphocyte ratio (PLR), neutrophil/lymphocyte ratio (NLR), and platelet count. These parameters were recorded and compared between the 2 groups. Results: The mean MPV and platelet count values were not significantly different between the two groups (p=0.473 and p=0.977, respectively). However, the median NLR and PLR values were significantly higher in the pyelonephritis group than in the cystitis group (p<0.001 and p=0.001, respectively). Conclusions: The NLR and PLR appear to be useful in differentiating between acute pyelonephritis and cystitis. However, there is a need for additional prospective studies with larger patient numbers.