Equipment Operation & Maintenance Flashcards

A laboratory's automated urinalysis analyzer is consistently misclassifying bacteria as yeast. What maintenance step should be performed FIRST?

Answer: Clean the optical flow cell and verify the system is free of debris

Debris or contamination in the optical flow cell can cause misclassification of particles; cleaning the flow cell is the first maintenance step to address optical interference.

Which of the following best describes 'carry-forward contamination' in an automated coagulation analyzer?

Answer: Residual clot material from a previous sample contaminating the next sample's reaction cuvette

Carry-forward contamination occurs when residual material from a previous sample (especially clots or fibrin strands) is carried into the next sample's cuvette, affecting results.

An electrolyte analyzer using ion-selective electrodes (ISEs) produces consistently elevated sodium results. After replacing the sodium electrode, results remain elevated. What is the NEXT troubleshooting step?

Answer: Recalibrate using a new calibrator lot with verified values

After electrode replacement, if results remain biased, the calibrator itself may be the source of error; verifying with a fresh lot of calibrator with certified values is the next logical step.

A laboratory technologist notices that the STAT coagulation analyzer's PT reagent has turned turbid after being loaded into the instrument. The correct action is:

Answer: Remove and discard the turbid reagent, load a new vial, and re-qualify before patient testing

Turbidity in PT reagent indicates deterioration (precipitation or microbial contamination); it must be discarded and replaced, and the analyzer re-qualified before resuming patient testing.

What is the primary purpose of performing a daily 'blank' reading on a photometric analyzer?

Answer: To set baseline absorbance and correct for background optical noise or reagent color

A blank reading establishes the baseline (zero absorbance) by accounting for any inherent color or optical noise in the reagent or cuvette, ensuring accurate sample measurements.

During mass spectrometer maintenance, source cleaning is required when:

Answer: Ion suppression increases or sensitivity decreases despite good calibration

Matrix buildup on the ion source causes ion suppression and reduced sensitivity; source cleaning is indicated when these symptoms appear even with valid calibration.

A microbiology incubator used for blood culture bottles shows a temperature of 36°C instead of the required 35°C ± 1°C. Which statement is correct?

Answer: 36°C is within the ±1°C tolerance and no action is required beyond documentation

35°C ± 1°C means the acceptable range is 34–36°C; a reading of exactly 36°C is at the upper limit but still within tolerance, requiring only routine documentation.