Clinical effectiveness of serum lactate dehydrogenase as a screening biomarker for oral potentially malignant disorders and oral squamous cell carcinoma: An observational study

Background: Oral potentially malignant disorders (OPMDs), particularly oral leukoplakia (OL) and oral submucous fibrosis (OSF), carry a high risk of progression to oral squamous cell carcinoma (OSCC). Early detection remains difficult in low-resource settings, highlighting serum lactate dehydrogenase (LDH) as a promising non-invasive biomarker. Aim: To assess the clinical effectiveness of serum LDH as a screening biomarker among OL, OSF, and OSCC compared with healthy people. Materials and Methods: This comparative study involved 60 participants, equally distributed across 4 groups: healthy controls, OL, OSF, and OSCC. Serum LDH levels were analyzed using a standardized biochemical analyzer. Disease-specific clinical parameters of severity of disease (lesion diameter, inter-incisal distance, and tumor T stage) were recorded. Statistical analyses were used to find out differences between groups and relationships between LDH and clinical severity. Results: Disease-specific severity reflected moderate OL lesion size, restricted mouth opening in OSF, and intermediate OSCC stage. Serum LDH rose progressively from controls (166.3 IU/L) to OSCC (328.9 IU/L) ( P < 0.001). Receiver operating characteristic analysis showed strong diagnostic performance (area under the curve: OSCC 0.92; OPMDs 0.84). At 200 IU/L, sensitivity was 86.7% and specificity 93.3%, supporting LDH as a reliable screening biomarker. Conclusion: Serum LDH shows a stepwise elevation in severity from healthy mucosa to OPMDs and oral cancer. Although not disease-specific, LDH may be a promising adjunctive screening biomarker for early identification of OPMDs and OSCC, especially in resource-limited settings.