In medicine, we are often faced with interpreting a variety of laboratory studies and other tests. Ordering blood chemistry panels, complete blood cell counts, cultures from various sites in the body, radiologic studies, and other examinations to provide data is commonplace during almost every medical encounter and investigation. However, obtaining this data can be a double-edged sword. With every test or study that provides information to confirm or exclude a medical condition or aid in the management of an illness, there are other tests or studies that provide no useful information and may confound an investigation or cause harm.
On the surface, checking an electrolyte panel seems like a relatively benign evaluation. However, if the blood specimen is hemolyzed, the serum potassium level erroneously increases. A truly elevated serum potassium level can increase the risk for cardiac arrhythmias. So, knowing that the specimen is hemolyzed, do you ignore the elevated potassium level? How high would you expect the potassium level to be elevated, if the specimen is hemolyzed? Can you guarantee that the elevated serum potassium level is entirely caused by hemolysis of the blood specimen and not a true value? The answers to these questions are not clear-cut. And, what happens in most cases, the test is rechecked. Rechecking the test requires obtaining more blood. Obtaining more blood often requires another poke with a needle and subsequent pain, a longer length of stay, the use of further medical resources, and additional needless risks.
The same can be said for checking a head CT scan after a head injury. There needs to be a strong justification for performing the scan because the patient’s brain is exposed to a significant amount of radiation. Radiation is obviously not a benign particle. So, while you want the head CT scan not to show any abnormalities, you want to make sure that the risks of the CT scan are outweighed by the benefits of obtaining the study. Checking a CT scan with a high likelihood of it being normal doesn’t do the patient any favors and only unnecessarily exposes them to radiation that they shouldn’t have been exposed to in the first place.
Do you think that medical teams order too many unnecessary medical tests? Do you think that patients or patients' families ask for too many unnecessary medical tests?