From: howdHol@yaooho.com   
      
   usenet@only.tnx (Questor) wrote   
      
   > Recently I've had to get blood drawn for tests, and I can understand   
   > the desire to reduce that need to just a finger prick.  But it seems   
   > obvious to me that with such a small sample, there are going to be   
   > more problems getting an accurate measurement of the indicating   
   > compounds being sought in the test.   
      
   The book Bad Blood did a good rundown of the hurdles.   
      
   Small sample size was definitely one. She wanted to be able to use one   
   drop of blood for a dozen or more tests, and a lot of tests can't be   
   conducted on the same sample, meaning Theranos had to subdivide drops,   
   making the sample for tests even smaller. They simply didn't have the   
   accuracy they needed.   
      
   Another was the skin on a finger is typically a lot dirtier than the   
   skin on the inside of your arm, and that includes the inner layers of   
   skin. They had a lot more challenges with contamination of the needles   
   as they pushed through the skin, which worsened the problems of small   
   sample size.   
      
   Another is that the blood in fingertips is often a less accurate   
   representation of someone's blood in general than a sample taken from a   
   vein.   
      
   I seem to recall Theranos tried to come up with all kinds of algorithms   
   to adjust for these issues, but they never came close. They had   
   engineers and advisors who tried to tell Holmes and other top managers   
   about these problems, but they refused to listen.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)