The test is suitable, for instance, for monitoring and testing of wastewater, from electroplating and copper etching process as This screening test is a quick test to detect high chloride levels in water and wastewater that might cause interference with official COD methods. The test is in accordance with the ISO 15705:2002 method, and indicates within seconds a YES/NO possibility of having chloride interference on COD measurements. The kit can be used for checking 1000 ppm chloride concentration for the ISO COD testing, or for a 2000 ppm chloride check for the USEPA, APHA, AWWA and WEF methods.