Medical Laboratory Technician Laboratory Operations and QC 1 Flashcards
6 cards from real Medical Laboratory Technician Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Medical Laboratory Technician Laboratory Operations and QC 1 flashcards as text
A QC chart shows seven consecutive control values all falling on the same side of the mean. Which Westgard rule does this pattern violate?
Answer: 10x rule
The 10x rule is triggered when ten consecutive control measurements fall on the same side of the mean, indicating a systematic shift or bias in the method. Seven consecutive points on one side is an early warning of the same trend, and the 10x rule specifically addresses this systematic error pattern.
Which of the following best describes the chain of custody in a laboratory setting?
Answer: A record documenting every individual who handled a specimen from collection to final disposal
Chain of custody is the documented record tracking every person who collected, transferred, received, or tested a specimen. It is essential in medicolegal cases to ensure specimen integrity and admissibility of results in legal proceedings.
A technician notices that a reagent bottle has been open for three weeks, but the manufacturer's stability after opening is listed as two weeks. What is the most appropriate action?
Answer: Discard the reagent and open a new bottle
Reagents used beyond their open-vial stability period must be discarded regardless of current QC performance, because degradation may not yet be detectable but can compromise result accuracy. Following manufacturer guidelines for stability is a fundamental QC principle.
What is the purpose of a calibration verification procedure in the clinical laboratory?
Answer: To confirm that the measuring system can accurately reproduce results across its reportable range
Calibration verification confirms that a calibrated instrument continues to accurately report patient values across its entire analytical measurement range (AMR). It is required at defined intervals and whenever calibration is performed, a major maintenance event occurs, or QC repeatedly fails.
Which of the following is an example of a pre-analytical error?
Answer: A blood sample collected in the wrong tube type for the ordered test
Pre-analytical errors occur before the specimen enters the testing phase and include mistakes in collection, labeling, transport, or tube selection. Using the wrong anticoagulant tube can falsely alter test results, making this a classic pre-analytical error.
A new method is being compared to the current reference method using patient samples. Which statistical parameter best expresses the average difference in results between the two methods?
Answer: Bias
Bias is the systematic difference between the mean result of a new method and the mean result of the reference method. While the correlation coefficient shows how linearly related the two methods are, it does not reveal whether one method reads higher or lower than the other — bias quantifies that difference directly.