This study was conducted in the clinical laboratory in the department of biochemistry, Government medical college, Jalgaon for a period of 3 months . A total of 30 subjects were taken randomly and 2 ml blood was collected in each of the F/OX bulb and plain bulb by phlebotomy after a rest of 30 minutes.The blood lactate was measured at 0 hrs (within 15 minutes), 24 hrs and 48 hrs from both F/OX bulb and plain bulb.For the Quantitative measurement of plasma lactate, enzymatic lactate oxidase–peroxidase method was employed .We observed a significant change in blood lactate level in plain bulb preserved in 2–8oC after 24 hours and 48 hours as compared to F/OX bulb preserved in 2–8oC. The stability of lactate in F/OX preserved sample was maintained for 48 hours.Thus we conclude that F/OX bulb should be preferred over plain bulb to measure the lactate level