Laboratories of Clinical Pathology, Biochemistry and Microbiology attached to  Ayothidoss Pandithar Hospital do the required investigations, free of cost, for OP/IP patients. Qualified Lab-technicians and PG scholars of Noi Nadal Department do investigations (both Modern and Siddha) under the guidance of the faculty members of the Noi Nadal Department. Specific Siddha methods of diagnosis - Envagai Thervu including Urine examination - Neerkkuri and Neikkuri, are done in the laboratory for OP/IP patients.