Working in a hospital laboratory, one can see the complexity behind a simple doctor's visit. There are many steps, and many points at which a critical error could be made. For example, say an elderly person comes in and has a suspected vitamin B-12 deficiency and a couple sores on the arm which resemble community acquired methicillin-resistant staphylococcus aureus (MRSA). So the doctor talks to the patient, swabs the wound to be cultured, suggests using multi-antibiotic ointment on the sores, and recommends eating supplements or food rich in B-12, while scheduling a follow-up appointment. At this point, the patient feels he has been treated and leaves the office, goes downstairs for a B-12 blood test and is feeling pretty good.
What the patient doesn't see is the many steps of labeling the culture tube and blood sample, tracking the sample on multiple packing lists, how long the blood sample is sitting around unspun and unaliquoted (B-12 is sensitive to light and temperature - must be put in a light-protected tube and frozen). Any one of these steps could lead to a wrong diagnosis - the B-12 could break down, the patient's medical record number could be typed in incorrectly when labels are printed, an incomplete order could result in the sample sitting around for a day or two, while aliquoting the tech could put the wrong label on the new light-resistant tube, etc. There are so many variables involved in laboratory science, it's a wonder that there are not more misdiagnoses. Maybe there are. Something has to be said for the work these people do - there is a huge volume of samples and patients to process in a given day compared to what doctors see, and they often put in extra hours or forego breaks to make sure everything is processed and sent out on time. However, most of these people, from couriers to lab assistants to receptionists, do not have more than a high school education, are overloaded with information about hospital protocol, and are constantly rushed, so mistakes inevitably happen.
After working in the lab, there are a few things I will take with me to medical school: always be courteous to hospital personnel, regardless of their position; take sensitive lab tests with unexpected results with a grain of salt - do a retest to be certain; make my instructions, particularly written instructions, as simple and clear as possible; always pick up my phone in case the lab or other department is calling for a clarification; and keep up-to-date on hospital protocols, in case test names/codes have changed or if certain tests can only be performed at specific locations.