Presence-absence (P-A) is a test that depends on a colour change to indicate the presence of contamination. If the test turns out to be positive, meaning the indicator bacteria is present, the water sample will change to a specific colour. P-A tests will not tell you the number of indicator bacteria in the water sample.
This demo will show how to conduct a PA test using Hach Pathoscreen medium.
Presence-absence (P-A) is a test that depends on a colour change to indicate the presence of contamination. If the test turns out to be positive, meaning the indicator bacteria is present, the water sample will change to a specific colour. P-A tests will not tell you the number of indicator bacteria in the water sample.
This demo will show how to conduct a PA test using Hach Pathoscreen medium.
Can’t find what you need? Have more questions about a topic? Need advice on how to use a resource? Chat with a CAWST advisor.
Contact usCAWST is a Canadian charity and licensed engineering firm. We address the global need for safe drinking water and sanitation by building local knowledge and skills on household solutions people can implement themselves.