Sudden deafness poses a significant threat to patients' quality of life, yet effective indicators for evaluating its onset and prognosis remain elusive. The inner ear is primarily supplied by the labyrinthine artery, which lacks collateral circulation. Changes in coagulation function and hemorheology can cause spasm or thrombosis of the labyrinthine artery, leading to ischemia, hypoxia, and microcirculation disorders in the inner ear, ultimately resulting in sudden deafness. This retrospective study examined 196 patients with sudden deafness, utilizing the 2015 Chinese guideline for diagnosis and treatment classification. Coagulation system analysis used the STA-R Evolution automatic coagulation analyzer, measuring activated partial thromboplastin time (APTT), prothrombin time (PT), and fibrinogen (FIB). Plasma lactate concentration was determined using a Johnson and Johnson Fusion 5.1 model plasma lactate detector. Results of the study revealed a correlation between the degree of hearing loss and disease prognosis. Patients with higher grade hearing loss exhibited elevated plasma lactate levels upon admission compared with those with lower grade hearing loss. Importantly, elevated plasma lactate levels at admission served as predictive indicators for treatment outcomes. In addition, patients with ineffective treatment demonstrated a more coagulable blood state, as evidenced by the lower APTT (ineffective treatment: 31.47 ± 4.55 seconds, effective treatment: 35.17 ± 5.38 seconds) and PT on admission, but higher plasma FIB. In conclusion, plasma lactate levels upon admission hold promise as prognostic markers for sudden deafness treatment outcomes, providing valuable insights for clinical management.