What is the purpose, for bigger ships, of marine lubricant sampling?

An analysis of the oil being used is an indispensable diagnostic tool to rapidly identify a poor functioning of the engine or the end of the useful life of the lubricant. The test results allow the crew to monitor the engine's condition and to take prompt action if and when necessary. The large number of tests, standardized around the world, take account of the type of engine, the fuel used, the way in which it is used and the environmental conditions of the ship.