Question 1

Which of the following organizations provides oversight and governs the use the radioactive materials in the clinical laboratory?

Accepted Answer

The Nuclear Regulatory Commission (NRC) is responsible for overseeing and governing the use of radioactive materials in the clinical laboratory. The NRC is an independent agency of the United States government that regulates civilian use of nuclear materials to ensure public health and safety, promote the common defense and security, and protect the environment. The other options listed do not have jurisdiction over radioactive materials in the clinical laboratory.

Question 2

The delivery of accurate voltage and current by an electrophoresis power supply should be checked how often?

Accepted Answer

D

Question 3

A lavender-top tube labeled "John Smith" is received in the molecular biology laboratory. The tube is attached to a requisition stamped "John Doe," with today's date, requesting testing for t(9:22). Which of the following describes the proper course of action for the technologist who receives this specimen?

Accepted Answer

The labeling discrepancy between the tube and requisition is a potential error that could lead to patient misidentification and incorrect test results. The laboratory supervisor should be notified immediately so that the issue can be addressed and the correct patient can be identified. It is important to prioritize patient safety and follow proper protocols for resolving labeling discrepancies.

Question 4

What is required for incorporating an FDA-approved test into a laboratory?

Accepted Answer

The answer of What is required for incorporating an FDA-approved...

Question 5

An unlabeled specimen arrives in the laboratory with an accompanying requisition. The requisition is properly filled out. How should you proceed?

Accepted Answer

It is not safe to proceed with testing an unlabeled specimen, even if the requisition is properly filled out. This could lead to misidentification and errors in patient care. The supervisor should be notified so that a proper labeling process can be established before proceeding with testing.

Question 6

Whole blood was sent to the laboratory for viral load determination of HIV (an RNA virus). It was received on a Saturday morning, and the technologist working in the receiving section of the laboratory put the tube in the refrigerator at 2^o-8^oC. The molecular technologist came on Monday morning and collected the specimens that had been sent to the laboratory over the weekend. What will likely be required on Monday morning?

Accepted Answer

The blood sample was left in the refrigerator for two days, which may result in sample degradation and inaccurate viral load results. Therefore, the best course of action would be to request a blood redraw for accurate testing.

Question 7

A technologist in a tissue bank who performed HLA typing by DNA analysis was asked to bank all DNA extracted from specimens received in the laboratory so as to maintain the nucleic acid for the longest period in the most limited space. How should the DNA be stored to satisfy this request?

Accepted Answer

The answer of A technologist in a tissue bank who...

Question 8

An outbreak of Salmonella has occurred in the community. Molecular-based assays will be performed to determine if multiple isolates of Salmonella taken at hospital X are related to each other and part of the outbreak. Laboratory technologists have accumulated 10 different cultures growing Salmonella and suspect that there may be more isolated in the next few days. How should these organisms be handled until the molecular-based assays can be performed in about 3 days?

Accepted Answer

The answer of An outbreak of Salmonella has occurred in...

Question 9

Which is used to calibrate an instrument that measures analyte in saline?

Accepted Answer

A reference standard diluted in saline is the best choice for calibrating an instrument that measures analyte in saline because it mimics the matrix of the sample being tested. A positive control diluted in water or an unknown patient sample diluted in saline may not accurately reflect the matrix of the actual samples being tested. A reference standard diluted in water may not accurately reflect the matrix of the saline samples being tested.

Question 10

An unlabeled bottle of clear liquid is found on a shelf. A sign on the shelf says, "Tris-EDTA Buffer, pH 8.0." What is the proper course of action?

Accepted Answer

The proper course of action when encountering an unlabeled bottle of clear liquid is to dispose of it safely. Without proper labeling, there is no certainty about the contents, making it unsafe to use or test through tasting or pH measurement. Safety protocols in laboratories and other settings where chemicals are used dictate that unidentified substances should be considered hazardous and disposed of according to established procedures.

Question 11

Which of the following controls can distinguish between a true negative in a nucleic acid amplification assay from a false negative in which amplification failed in the specimen?

Accepted Answer

An amplification control is used to distinguish between a true negative result and a false negative result due to failure of the nucleic acid amplification process. It ensures that the amplification step worked properly for the specimen being tested.

Question 12

Which of the following organizations has established standards used by laboratory professionals when developing, implementing, and performing molecular-based laboratory tests?

Accepted Answer

The Clinical and Laboratory Standards Institute (CLSI) is a global organization that develops and publishes standards for the laboratory testing industry, including molecular-based laboratory tests. These standards are used by laboratory professionals to ensure accuracy, reliability, and consistency in testing procedures. The other organizations listed do not specifically focus on establishing laboratory testing standards.

Question 13

Which test method is best for a fixed tissue specimen?

Accepted Answer

The answer of Which test method is best for a...

Question 14

A blood sample is received in the laboratory for factor V Leiden analysis. What precautions are appropriate?

Accepted Answer

Standard precautions are appropriate for handling blood samples for factor V Leiden analysis. These precautions include wearing gloves, a gown, and eye protection when there is a risk of exposure to blood or other bodily fluids. This is because the sample may contain blood-borne pathogens that can be transmitted through contact with the blood, such as HIV or hepatitis B and C.

Question 15

A blood specimen is received in the laboratory for a PCR assay to detect cytomegalovirus (a DNA virus) on a Wednesday night. The PCR assay will not be performed until the next Monday morning. How should this specimen be stored to maintain the integrity of the nucleic acid prior to analysis?

Accepted Answer

The specimen should be stored at -20°C to maintain the integrity of the nucleic acid prior to analysis. Lyzing RBCs and centrifuging the specimen are not necessary for PCR analysis. Whole blood can also be stored but at a lower temperature (-20°C) to prevent degradation of the DNA. Storing at room temperature or higher (22-37°C) can accelerate the breakdown of DNA.

Question 16

The ability of a molecular-based assay to detect only the analyte and not other targets is called which of the following?

Accepted Answer

Analytic specificity refers to the ability of a test to correctly identify only the target analyte and not other related substances or interfering factors. Clinical specificity refers to the ability of a test to correctly identify those without the disease being tested for. Clinical sensitivity refers to the ability of a test to correctly identify those with the disease being tested for. Analytic sensitivity refers to the lowest concentration or amount of the target analyte that a test can detect.

Question 17

An assay that detects an analyte associated with a particular disease only in patients who have that disease and not in patients who do not have the disease has which of the following?

Accepted Answer

Clinical specificity. Clinical specificity refers to the ability of a test to correctly identify patients who do not have a disease. In the given scenario, the assay detects an analyte only in patients who have the disease and not in patients who do not have the disease. Therefore, the assay has high clinical specificity. Analytic specificity refers to the ability of a test to correctly identify and measure the analyte of interest without interference from other substances. Analytic sensitivity refers to the ability of a test to correctly detect small amounts of the analyte of interest. Clinical sensitivity refers to the ability of a test to correctly identify patients who have the disease.

Question 18

The temperature in a refrigerator that is used to store patient specimens and reagents should be checked how often?

Accepted Answer

The temperature in a refrigerator used to store patient specimens and reagents should be checked at least once a day to ensure that the temperature remains within the acceptable range. This ensures the integrity and accuracy of the stored specimens and reagents. Checking the temperature hourly (A) or biweekly (C) may be excessive or not frequent enough, respectively, while checking it weekly (D) may not be frequent enough to catch any temperature fluctuations that could affect the specimens and reagents. Therefore, checking the temperature daily (B) is the best choice.

Question 19

A quantitative method was performed 100 times, and results from 99 of the 100 runs were in agreement with each other. This method has 99%:

Accepted Answer

Precision is the measure of how close the results are to each other, regardless of whether they are correct. Since 99 out of 100 results agree with each other, this indicates high precision.

Question 20

Which of the following controls defines the lower limit of reproducible and accurate detection of a molecular target?

Accepted Answer

Sensitivity is the control that defines the lower limit of reproducible and accurate detection of a molecular target. It refers to the minimum amount of target molecule that can be reliably detected and distinguished from noise. The positive and negative controls help to evaluate the specificity and overall performance of the assay, while amplification refers to the process of increasing the amount of DNA or RNA in the sample, which can improve detection but is not a control for sensitivity.

Quiz 16: Quality Assurance and Quality Control in the Molecular Laboratory