Lesson 5 — The Clinical Laboratory
All procedural steps, PURPOSE rationales, and topic content below are verbatim from MedCerts HLT420A Storyline modules. Quiz items have been normalized to multiple-choice format with verbatim source rationales. Reference textbook: Niedzwiecki & Pepper, Kinn's The Clinical Medical Assistant, 15th ed., Chapter 31. No outside material added.
- Discuss laboratory personnel, divisions, and types of testing
- Recognize organizations involved with safety in the clinical laboratory
- Define CLIA-waived testing and types of tests
- Differentiate chemical and physical hazards in the laboratory setting
- Describe OSHA laboratory safety and bloodborne pathogens standards
- State process for specimen collection, processing, storage, and equipment use
- Summarize the potential role of the medical assistant in the clinical laboratory
Glucometer Quality Control
Goal: To test and analyze the results of glucometer controls to see whether a glucometer is producing reliable test results, and to record the results on the laboratory flow sheet.
- Disposable gloves
- Glucometer
- Coded test strips designed for the glucometer used
- Control solution provided by the manufacturer
- Package insert showing directions on how to run the glucometer
- Biohazard waste container
- Glucose test control flow sheet
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Sanitize your hands and put on disposable gloves.Purpose
All controls and specimens are considered biohazardous.
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Take a coded strip and note the control level and range listed on the control bottle or the strip container.
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Review the directions on the glucometer package insert and calibrate the meter by inserting the pre-coded test strip into the monitor or by manually inserting the code number into the monitor.Purpose
Manufacturers must provide directions on how to calibrate light-sensitive meters every time a new container of test strips is used.
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Check the expiration date on the liquid control bottle and mix well by inverting and rolling the bottle between your hands.Purpose
If the control bottle date is expired, the control cannot be run. And, it is crucial to have all the reagents in the bottle in suspension to produce reliable results.
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Complete the top portion of the control log sheet with the test name, control lot number, and expiration date.Purpose
All this information is checked each time a control is run to compare the results of the same control.
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Insert your strip into the glucometer and apply a drop of the liquid control to the strip according to the directions.Purpose
The manufacturer must supply clear directions that are consistent every time a control or patient specimen is run.
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Record the result on the glucose test control flow sheet and note whether it falls within the manufacturer's reference range. If not, the test should be repeated with a new strip.Purpose
An occasional "out of range" result can occur. If the repeated new strip is back in range, proceed with patient testing. If the second strip falls outside the range, the patient may not be tested until the cause of the error is determined.
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When you have finished running the controls, dispose of the strips, remove your gloves, and sanitize your hands.
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Observe all the results obtained and compare them to the control ranges provided on the test strip bottle and/or liquid control bottle. Ask yourself these questions: Accuracy: Did all the results fall near the middle of the reference range? Precision: Were the results consistently close to each other (without extreme highs and lows)?Purpose
To prove Reliability: If both questions are affirmed, the test is reliable and the glucometer may be used to test patients.
Microscope Use
Goal: To focus the microscope properly using a prepared slide under low power, high power, and oil immersion, and to perform routine maintenance on the microscope before storing it.
- Microscope
- Lens cleaner
- Lens tissue
- Slide containing specimen
- Immersion oil
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Sanitize your hands.
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Gather the needed materials.
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Clean the lenses with lens tissue and lens cleaner.Purpose
Dust on lenses can obscure elements in the microscopic field.
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Adjust the seating to a comfortable height.
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Plug the microscope into an electrical outlet and turn on the light switch.
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Place the slide specimen on the stage and secure it.
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Turn the revolving nosepiece to engage the 4× or 10× lens.Purpose
Always begin microscopic observations at low power.
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Carefully raise the stage while observing with the naked eye from the side.Purpose
Observing from the side prevents breaking of the slide if the coarse adjustment knob is advanced too far.
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Focus the specimen using the coarse adjustment knob.Purpose
The coarse adjustment knob quickly brings the specimen into focus.
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Adjust the amount of light by closing the iris diaphragm, by bringing the condenser up or down, or by adjusting the light from the source.Purpose
Too much light when the low-power objective is used can be irritating to the eyes.
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Switch to the 40× lens. Use the fine adjustment knob to focus the specimen in detail.
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Turn the revolving nosepiece to the area between the high-power objective and oil immersion.
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Place a small drop of oil on the slide.Purpose
Immersion oil has nearly the same refractive index as glass and prevents refraction of the light, thus improving resolution.
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Carefully rotate the oil immersion objective into place. The objective will be immersed in the oil.
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Adjust the focus with the fine adjustment knob.Purpose
The fine adjustment knob moves the objective slowly, preventing damage to the microscope and the slide.
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Increase the light by opening the iris diaphragm and raising the condenser.Purpose
Lighting is crucial to microscopy; the higher the magnification, the more light that is needed.
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Identify the specimen, Return to low power but do not drag the 40× lens through the oil.
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Remove the slide and dispose of it in a biohazard container.
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Lower the stage, Center the stage.Purpose
Returning the microscope to this position protects it during storage.
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Switch off the light and unplug the microscope. Clean the lenses with lens tissue and remove oil with lens cleaner.Purpose
Dust and oil must be removed from the lenses after a procedure.
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Wipe the microscope with a cloth.
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Cover the microscope.
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Sanitize the work area.
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Sanitize your hands.Purpose
Medical Asepsis.
Knowledge-check items
Click an answer to lock it in — you'll see the rationale below. Reset any time to re-attempt. Items originally formatted as true/false, fill-in-blank, or drag-and-drop have been normalized to multiple choice; the source format is noted in the eyebrow.
L05-01 · Glucometer Quality Control
"If not, the test should be repeated with a new strip."
When control results fall outside the reference range, the procedure requires repeating the test with a new strip to determine if the result was an anomaly or if there is a genuine equipment problem.
L05-02 · Microscope Use
"Clean the lenses with lens tissue and lens cleaner."
Lens cleaner is the correct cleaning agent used with lens tissue to remove dust from microscope lenses, which can obscure the microscopic field.
"Immersion oil has nearly the same refractive index as glass and prevents refraction of the light, thus improving resolution."
Immersion oil prevents refraction of light, which allows for better resolution and clearer visualization of the microscopic specimen.
"Cover the microscope."
Covering the microscope is the final step in proper maintenance and storage procedures to protect the equipment from dust and damage.