Blood tests: essential or excessive?

Perhaps one of the most widely used medical investigations is the humble blood test. Or is it quite so humble? As a medical student, I took a part time job taking blood as a phlebotomist at my local district hospital. Often the perception amongst phlebotomists is that blood tests become the addictive habit of newly graduated nervous doctors. Weekend requests are apparently “urgent only.” Yet, with 17 requests a ward on a Sunday morning, you wonder how many of the results will even be reviewed. Surprisingly, we find that “extremely urgent” patient X has gone home, or “very seriously sick” patient Y has gone for a morning walk.

Blood tests are important in clinical practice. But is it possible to put a little more thought into requesting tests? Apart from some phlebotomist agitation, there are important factors at stake. In fact, unnecessary testing may cause significant reduction in blood volume in critically ill patients.1

Although blood tests are considered to be cheap, overuse of any service may …