Laboratory Practice Flashcards
7 cards from real STP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Laboratory Practice flashcards as text
What is the appropriate response when a laboratory worker discovers an unlabeled container of unknown liquid?
Answer: Treat it as hazardous, label it 'Unknown,' isolate it, and report it to the safety officer
Unknown chemicals must be treated as hazardous, properly quarantined, and reported so they can be characterized safely before any further handling or disposal.
In the context of laboratory quality systems, what does 'traceability' mean for a measurement result?
Answer: The property of a measurement result that can be related to a stated reference through an unbroken chain of calibrations
Metrological traceability links a measurement result to a national or international standard through an unbroken documented calibration chain.
Which of the following best describes the purpose of a blank sample in an analytical run?
Answer: To detect background signal, contamination, or matrix interference in the absence of the analyte
A blank contains all components of the assay except the analyte, so any signal detected indicates background noise or contamination.
When working with a biological safety cabinet (BSC), which action will DISRUPT the protective airflow and should be avoided?
Answer: Rapidly moving arms in and out of the cabinet
Rapid arm movements across the cabinet opening create turbulence that disrupts the air curtain, allowing potential cross-contamination or exposure.
A pipette is calibrated to deliver 1000 µL. During a gravimetric check using water at 20°C, it consistently delivers an average of 985 µL. This is an example of:
Answer: Systematic error (bias) with acceptable precision
A consistent offset in the same direction from the true value represents systematic error (bias), which can often be corrected through recalibration.
Under OSHA's Bloodborne Pathogen Standard, what is the engineering control required to minimize needlestick injuries?
Answer: Using safety-engineered sharps devices with built-in protection mechanisms
OSHA mandates the use of sharps with engineered sharps injury protections (SESIPs) as the primary engineering control to prevent needlestick injuries.
What is the purpose of running a quality control (QC) sample at the beginning of each analytical batch?
Answer: To verify that the analytical system is performing within acceptable limits before results are reported
QC samples with known values confirm that the assay and instrument are performing correctly before patient or experimental results are accepted.