December 26, 2018 3:09 AM EST
A large proportion of the public has a perception that blood tests are simple things and when performed, almost always result in a yes or no answer giving you the solutions that you wanted. However, in a lot of cases I have found that when I order my own lab tests, they can turn out to be misleading rather than a predictor of something.
One such example is of pregnancy test from a urine specimen. These tests when performed due to a missed or late period often yield highly accurate results and has sensitivity and specificity. However, there are cases when the values from blood tests cannot be relied upon. One such example is of thyroid antibodies which can and cannot be an indicator of thyroid disease and even with values that favour disease positivity, clinical correlation is necessary to establish a firm diagnosis.