Any medical test will sometimes fail to detect a condition when it is present and indicate that <b>there is one</b> when there is none.<br/><br/>Guys,<br/><br/>what does <b>there is</b> refers to in above sentence? Can someone help me to understand the usage of <b>one?</b><br/><br/><b>Thank you</b><br/><br/><b>POK</b>