Tumor markers are the substances which quantitatively change in serum during tumor development. They have now been introduced in the diagnosis of potentially malignant disorders (PMDs)& malignant lesions. One such is Lactate Dehydrogenase (LDH) which is found in cells of almost all body tissues. LDH activity in serum increases as a marker of cellular necrosis. Serum LDH levels have been used as a biochemical marker in diagnosis of various body cancers. Profile of salivary LDH is similar to that found in oral epithelium indicating major source of salivary LDH is probably the oral epithelium shedding cells.

Aims and objectives: The current study was aimed to measure and compare LDH levels in serum and saliva in patients of oral sub mucous fibrosis (OSMF), oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC).

Materials and methods: Clinically diagnosed and histopathologically confirmed 10 cases each of OL, OSMF and OSCC were selected and compared with control. After taking an informed consent, serum and unstimulated whole saliva was collected and processed for LDH measurement using LDH ERBA KIT.

Results: Increased LDH activity is seen in both serum as well as saliva in patients with OL, OSMF and OSCC in comparison to control.

Conclusion: salivary LDH estimation can prove to be a valuable substitute to serum LDH as a biochemical marker as it is a simple, non–invasive procedure and easily accepted by the patients.