Microscope Care and Use
A microscope is an essential piece of equipment for any veterinary laboratory. It is used on a daily basis to analyze blood, urine, fecal and cytological samples. Without proper care and maintenance, however, this invaluable tool will not perform adequately for the technologist.
Focusing and examining samples
When preparing to examine a sample, the slide should be placed on the stage, specimen-side up, and held in place with the stage brackets. Ensure that there is no moisture on the stage or on the back of the slide as this will impair its ability to move freely. Roughly center the specimen and rotate the 10X objective into place. Find focus under the 10X and increase your objective power to 40X and then 100X. With each step, re-center your specimen in your field of view and adjust your focus using the fine focus adjustment knob. When moving to 100X (oil immersion), add one drop of immersion oil to the slide and rotate the 100X objective into place. The lens of the objective should make contact with the oil and slight fine focus adjustment may be required to sharpen the image.
Depending on the sample that is being viewed, the iris diaphragm and/or the condenser can be adjusted to modify the contrast. Typically, liquid samples, such as unstained urine, are best viewed with a lower light and increase contrast, while the detail of stained blood smears is best viewed with a brighter light.
Key Microscope Components
Cleaning and Maintenance of the Microscope
After each use, the oculars, objective lenses, stage and stage brackets should be thoroughly cleaned and the entire microscope should be cleaned daily. Frequent, regular cleaning will ensure that the microscope stays in good working order.
Objectives and Ocular lenses
Care should be taken when cleaning the objective and ocular lenses. Using the appropriate cleaning solutions will ensure that any delicate components of these lenses will not be damaged or corroded over time. Commercial lens cleaning solutions work well as they will not damage the lenses and do not leave any streaks or residue. Distilled water is another suitable option, however it may not be as effective in clearing fingerprints or oily residue.
Kim wipes and other non-abrasive tissues are appropriate as they will not scratch the lens surfaces and do not leave lint behind. The use of other cleaners and tissues/cloths should be restricted to the stage and body of the microscope. If there appears to be dust particles in the field of view, these are best cleared with compressed air. The oculars can be removed to provide more access. To help minimize dust in general, use a dust cover over the microscope when not in use.
Conclusion
When properly maintained, a microscope can be a useful piece of equipment when its needed. Taking a proactive approach means less down time for equipment maintenance which often results delays of sample processing. Every team member can do their part to maintain their practice’s investment.
Key Points
Clean objective lenses and oculars after every use.
Clean heavily soiled or oily areas last to avoid tracking the residue to other parts of the microscope.
Cover the microscope when not in use.
Turn the light off when not in use to extend the bulb life and minimize heat.
Emphasize the important of regular maintenance and encourage all staff members to follow protocols.
Service microscopes annually using a professional service.
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Hendrix, Charles M., and Margi Sirois. Laboratory Procedures for Veterinary Technicians. Mosby Elsevier, 2007.
Bassert, Joanna M., et al. McCurnin's Clinical Textbook for Veterinary Technicians. Elsevier Saunders, 2018.