<prompt> Translate the following text to EnglishIli kuamua bora ya skrini zilizopo, majaribio ya kituo cha multicenter na mchanganyiko mkubwa wa idadi ya watu na idadi kubwa ya wagonjwa waliofanyiwa skrini tofauti zinahitajika.  <response>: To determine the best of the available screens, a multi-center trial with a broad demographic mix and a large number of patients subjected to different screens is needed. 