an improved , copolymer - based immunoassay system , method , and apparatus is highly sensitive and effective in accurately measuring extremely low concentrations , such as 10 - 6 to 10 - 12 grams per milliliter , of biologically active substances , such as monoclonal or polyclonal antibodies and antigens , cancer markers , proteins , bacteria , viruses , therapeutic drugs , drugs of abuse , and food and water contaminants in fluid samples . the system requires no sample preparation , and is reliable , easy to use , sufficiently low in cost to be readily usable in doctors &# 39 ; offices , small labs , and other low - volume facilities , but is also readily adaptable to hospital and high - volume use . the new system , method , and apparatus for agglutination immunoassay systems includes novel and coordinated carrier particle technology , light application and measurement and chemistry , coacting to provide the multiple advantages of simplicity and accuracy in use , and extreme sensitivity in application , in quantifying immunoassays .