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So all blood tests are useless?

• dingo_bat 10y ago
  Blood tests use a relatively large amount of blood to counter the problem. Also many blood tests are repeated multiple times before the doctor produces the final diagnosis. So multiple units of blood from a vein distributed over days vs a pinprick's worth of blood from a finger.
  • Noseshine 10y ago
    Also, blood found in a relatively large vein is much closer to the body average than that found in a capillary area, where much of the liquid is from extracellular space and not even coming from within blood vessels. Of course, extracellular space is filled from blood serum, but a lot of stuff has different concentrations in ECF.