Microscopy

Microscopy has gone out of style in medical education. Yet schools struggle to revise curriculums for various philosophical goals one of which is providing more primary care physicians. I cannot imagine practicing medicine without a microscope, much less primary care in a rural community.

The microscope needs to come back to medical school for use at multiple levels: Histology, embryology, microbiology and hematology. If students do not use a microscope in school, they will not use one in practice. In a rural clinic without nearby hospital or laboratory support, the microscope becomes once again the essential frontline diagnostic instrument. Reference labs and small hospital l abs will miss many key findings through delay in processing the specimen, temperature variations in the mail, through automation and, sometimes, unskilled technicians.

OK, the Colter Counter now does the complete blood count (CBC). The price is the same, in fact higher, but the Coulter Counter cannot read the peripheral blood smear. Herein lays a great economic advance for the hospital administrator. The Coulter Counter requires less labor and labor at a non-professional and thus lower cost level. On the contrary, however, critical information may be missing. For instance, a college student with swollen glands, a sore throat and palpable spleen might have Mononucleosis or something worse. The peripheral smear, viewed under the microscope, can identify Mononucleosis and differentiate Mono from Leukemia. The automated Coulter Counter cannot. Today if you suspect Mononucleosis, you might request that the pathologist view a peripheral smear or rely on a blood test for Mononucleosis. The Coulter technician is not skilled in producing peripheral smears and the pathologist is expensive. Furthermore, a blood sample sent through the mail degrades with time temperature and handling.

One look is worth a thousand words. There is just no substitute for a direct look at the little buggers. A gram stain may be the best early identification of an organism causing pneumonia. You can instantly classify the bacteria by morphology and staining characteristics as streptococcus, diplococcus pneumonia, staphylococcus, and various others by direct vision. Various fluoroscopy techniques can improve the accuracy of the identification. Knowing what you are treating greatly improves the selection of antibiotics while you wait for the sensitivity tests to identify the agents and concentrations that will do the job. Unfortunately, laboratory technicians are not very good at reading gram stains. A technician will describe everything in order to make sure of covering all the bases. In other words describing everything fails to distinguish the pathogens from the normal flora of the throat and mouth. This requires judgment and experience -- even some clinical correlation. Sometimes the pathologist is not good at this task either – depending on which one you get. In order to contain costs, most hospitals do not have a PhD microbiologist in the laboratory; they rely on the rotating or even visiting pathologist to fulfill that role.

Recent techniques in electron microscopy and fluorescent microscopy overcome the wavelength limitation of light and visualize structures at a molecular or nanoscale level. When I was in medical school, I envied those with binocular viewing and those with a 35 mm camera attached. Today, look for digital imaging with a view on the computer screen.  We can instantly add images to the patient record.  Multiple substage filters facilitate further convenience. Immuno-fluoroscopy offers instant identification of many pathogens.   

One does not need the current level of technology, however, to make use of microscopy in a doctor’s laboratory.  All that is required is good lenses, well aligned with a selection of objective lenses on a rotating head and a good substage light source. Skill in its use is what counts.

An old but very helpful Laboratory manual by Muriel C. Meyers, a hematology professor at the University of Michigan gives detailed instructions for preparing slides. She also includes other office laboratory procedures not requiring expensive reagents.  Some content may be out of date but other content maybe overlooked by today’s hurried and mechanized procedures. This 129 page manual contains many forgotten incites. Clinical Laboratory Diagnosis and Essentials of Hematology, Bethell and Meyers http://babel.hathitrust.org/cgi/pt?id=mdp.39015009566343;view=1up;seq=116