Laboratory Equipment and Quality Questions and Answers Flashcards
6 cards from real MLPAO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Laboratory Equipment and Quality Questions and Answers flashcards as text
What is the Beer-Lambert Law and how is it applied in clinical chemistry spectrophotometry?
Answer: It states that absorbance (A) is directly proportional to the concentration of the analyte (c) and path length (b): A = εbc
The Beer-Lambert Law states A = εbc, where A is absorbance, ε is the molar absorptivity constant, b is path length, and c is concentration. Absorbance increases linearly with analyte concentration.
What is a 'delta check' in laboratory quality management?
Answer: Comparison of a patient's current result with their previous result to detect unexpected changes
A delta check compares a patient's current laboratory result with their previous result for the same test to flag unexpected or implausible changes that might indicate specimen mix-up, collection error, or laboratory error.
In hematology, what laboratory parameter is measured by the erythrocyte sedimentation rate (ESR) test?
Answer: The rate at which red blood cells settle in anticoagulated blood over one hour
The ESR measures the rate (in mm/hour) at which red blood cells settle in a vertical tube of anticoagulated blood over one hour. It is a non-specific marker of inflammation.
What type of quality control chart is used to monitor the mean and variation of laboratory analytical results over time?
Answer: Levey-Jennings chart
The Levey-Jennings chart plots QC results over time against mean and ±1, ±2, and ±3 SD control limits, allowing visual detection of shifts, trends, and random error in laboratory analytical performance.
What is the purpose of the daily performance verification (DPV) for point-of-care testing (POCT) devices?
Answer: To verify the POCT device performs within acceptable limits using quality control materials before patient testing
Daily performance verification using QC materials confirms that the POCT device (e.g., glucometer, i-STAT) is functioning correctly before patient results are generated, ensuring result reliability.
What does the coefficient of variation (CV%) measure in laboratory analytical performance?
Answer: The degree of random variation in a method expressed as a percentage of the mean
The CV% (coefficient of variation) expresses imprecision (random variation) as a percentage of the mean: CV% = (SD/Mean) × 100. Lower CV% indicates better precision.