CMLA Laboratory Equipment Operation & Maintenance 2

Question 1

What is the correct procedure when a centrifuge becomes unbalanced during operation?

Accepted Answer

Stop the centrifuge immediately and rebalance the tubes

Answer

An unbalanced centrifuge must be stopped immediately to prevent mechanical damage and potential injury from vibration or rotor failure.

Question 2

Which maintenance task should be performed on a microscope's objective lenses after each use?

Accepted Answer

Clean with lens paper and approved lens cleaner

Answer

Lens paper with approved cleaner prevents scratching the optical glass while removing oil and debris from objective lenses.

Question 3

A laboratory refrigerator storing reagents reads 12°C instead of the required 2–8°C. What is the first action?

Accepted Answer

Adjust the thermostat and document the temperature excursion

Answer

The thermostat should be adjusted and the excursion documented so that reagent integrity can be assessed per laboratory protocol.

Question 4

What is the purpose of running a blank when using a spectrophotometer?

Accepted Answer

To zero the instrument against the solvent baseline

Answer

A blank containing all reagents except the analyte zeroes the instrument so absorbance readings reflect only the substance being measured.

Question 5

When calibrating an analytical balance, which of the following is critical?

Accepted Answer

External certified calibration weights must be used on a level, vibration-free surface

Answer

Certified weights on a level, stable surface ensure the balance reads accurately across its full measurement range.

(CMLA) Certified Medical Laboratory Assistant Practice Test