The gold standard for almost all the paper based diagnostic tests is the home pregnancy test called Clear Blue. What is forgotten is that this test was created in 1985 by a company called Unipath and this went on to become the most often used test that became a standard by which most diagnostic tests were compared to in the future. So what made this test great?
First the cost: being paper based and relatively simple the test made possible testing of pregnancy at home which had required expensive clinical testing.
The second the simplicity of the test: All it needed was some urine and that was all. This means no doctor was required, nor was any painful needles or expensive imaging equipment. All one had to do was to check for lines on the surface and that was it.
The third was the empowerment of people and getting the answer instantly instead of waiting to get the results from the doctor.
As diagnostic devices have gotten complicated and intricate, it is good to remember that Clear Blue like tests had these 3 characteristics that made them very popular and have almost not been replicated ever since.