Dental diseases, which exhibit high prevalence within the population, are frequently complicated by odontogenic inflammatory processes in the maxillofacial region (MFR), posing a significant risk of systemic septic complications. Procalcitonin (PCT) is a promising biomarker for the diagnosis of sepsis showing high sensitivity and specificity. However, its prognostic value for purulent inflammatory diseases of the maxillofacial region (PID-MFR) is still understudied. The study aimed to evaluate the diagnostic value of the PCT semi-quantitative rapid test for predicting septic complications in patients with PID-MFR and to evaluate the relationship between PCT levels and clinical/laboratory parameters. The study involved 60 patients (73.3% males, 26.7% females) aged between 21 and 71 years with PID-MFR. Serum PCT levels were determined by a semi-quantitative method. Patients were stratified into two groups: group 1 with PCT > 0.5 ng/mL (23.3%), group 2 with PCT < 0.5 ng/mL (76.7%). Septic complications were observed in 28.57% of patients in group 1, whereas no complications occurred in group 2 (p = 0.001; OR = 0.025). There were no significant differences in clinical and laboratory indicators, number of cellular maxillofacial spaces affected (3.7 ± 1.7), disease duration (5.17 ± 3.39 days), and length of hospital stay (6.50 ± 2.41 bed-days) between groups (p > 0.05). Our findings demonstrate that measuring PCT levels via a semi-quantitative method is an effective and accessible approach to predict septic complications of PID-MFR.