You know all those people on social media wanting mandatory drug testing for welfare recipients? Perhaps, reasonable in theory, if the test wasn't frequently producing false-positives and false-negatives. Making accurate clinical decisions is always challenging, but particularly with urine drug testing. The consequences of misinterpretation can be awful.

A look at some new data: COPD and Oxygen use - low serum creatinine levels - BMI considerations - the RDW - the age of blood.