Laboratory Equipment and Quality Flashcards

A Levey-Jennings chart for a quality control material shows that the last seven consecutive results have fallen above the mean. According to Westgard rules, this pattern is best described as a:

Answer: Shift

A 'shift' is a quality control pattern where six or more consecutive data points fall on the same side of the mean. This indicates a sudden, systematic change in the test system. A trend would show a gradual increase or decrease, while a random error would show no discernible pattern.

Which of the following is considered the most effective method for verifying that a steam autoclave cycle has successfully achieved sterilization?

Answer: Processing a biological indicator containing Geobacillus stearothermophilus spores

Biological indicators containing highly resistant bacterial spores, such as Geobacillus stearothermophilus, are the gold standard for validating sterilization. A successful cycle is confirmed when these spores are killed and fail to grow upon incubation. Chemical indicators and physical readings only confirm that certain conditions were met, not that sterilization was effective.

The routine performance verification for a laboratory centrifuge must include checking which two critical parameters to ensure proper specimen separation and quality?

Answer: Rotational speed (RPM) and timer accuracy

According to CLSI guidelines and best practices, the two most critical performance parameters to verify on a centrifuge are the rotational speed (tachometer reading) and the timer's accuracy. These ensure that the correct relative centrifugal force (RCF) is applied for the specified duration, which is essential for adequate specimen separation.

An MLA performs a gravimetric check on a P1000 micropipette set to dispense 1000 µL. The average mass of ten dispenses of reagent water is 0.982 g, which converts to a volume of 982 µL. This finding indicates a primary problem with the pipette's:

Answer: Accuracy

Accuracy is the measure of how close a dispensed volume is to the intended or set volume. Since the average volume (982 µL) is significantly different from the target volume (1000 µL), the pipette is inaccurate. Precision refers to the repeatability or closeness of the ten individual measurements to each other, which cannot be determined from the average alone.

A laboratory is setting up a highly sensitive trace element analysis. According to CLSI standards, what is the minimum grade of reagent water that should be used for preparing calibrators and standards for this procedure?

Answer: Clinical Laboratory Reagent Water (CLRW)

Clinical Laboratory Reagent Water (CLRW) is the minimum standard for most routine clinical analyses. It has defined limits for resistivity, bacteria, and total organic carbon. While some highly specialized tests may require Special Reagent Water (SRW) with even stricter limits for specific contaminants, CLRW is the established baseline for preparing most reagents, calibrators, and controls.

An MLA/T checks the temperature log for a specimen refrigerator and finds the current temperature is 10°C. The acceptable range is 2°C to 8°C. What is the most appropriate immediate action?

Answer: Document the out-of-range temperature and immediately notify a supervisor or senior staff.

When a critical piece of equipment like a specimen refrigerator is found to be out of its acceptable temperature range, the first and most critical step is to document the deviation and escalate the issue to a supervisor or lead technologist. This person will then direct the subsequent corrective actions, which may include transferring specimens and investigating the cause. Acting independently without notification could lead to further issues or improper handling of the situation.