Question 1

Which test method is best for a fixed tissue specimen?

Accepted Answer

C

Question 2

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 detect only the target analyte and not other substances, while analytic sensitivity refers to the ability of a test to detect small amounts of the target analyte. Clinical specificity and sensitivity refer to the test's ability to correctly identify positive and negative results in a clinical setting.

Question 3

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

Accepted Answer

A reference standard diluted in saline is the best choice to calibrate an instrument that measures analyte in saline. The reference standard is a known concentration of the analyte, which can be used to verify the accuracy of the instrument's measurements. Diluting in saline ensures that the matrix of the standard matches the matrix of the sample being measured.

Question 4

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 5

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 ability of a method to accurately detect and quantify small amounts of target molecules. Positive control refers to a sample that should always produce a positive result to ensure the accuracy of the test, negative control refers to a sample that should always produce a negative result to ensure the absence of false positives, and amplification refers to the process of increasing the number of copies of a specific DNA or RNA target sequence in a sample.

Question 6

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

Accepted Answer

The answer of The delivery of accurate voltage and current...

Question 7

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 the organization that establishes standards used by laboratory professionals when developing, implementing, and performing molecular-based laboratory tests. The other organizations listed have different roles in healthcare accreditation and professional development.

Question 8

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 all blood samples, which includes using gloves, lab coats, and other personal protective equipment to prevent exposure to blood-borne pathogens. Factor V Leiden analysis does not require additional precautions beyond standard precautions.

Question 9

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 centrifugation are not necessary for this task. Whole blood should not be stored at room temperature, as that can lead to degradation of the nucleic acids. Refrigeration at 4°C is another option, but it is not as ideal as -20°C storage.

Question 10

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 11

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

The scenario described refers to clinical specificity, which is the ability of a test to correctly identify those who do not have the disease or condition being tested for. Analytic specificity refers to the ability of a test to detect only the target analyte and not be affected by other substances in the sample. Analytic sensitivity refers to the ability of a test to detect small amounts of the target analyte. Clinical sensitivity refers to the ability of a test to correctly identify those who have the disease or condition being tested for.

Question 12

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

As the labeling on the tube and the requisition do not match, the proper course of action is to notify the laboratory supervisor. It is important to ensure that specimens are correctly labeled to prevent errors in testing and reporting of results. The supervisor may then investigate the discrepancy and take appropriate action to resolve it. The other options (A, B, and D) either ignore the discrepancy or attempt to resolve it without proper authority or verification, which could lead to errors and potential patient harm.

Question 13

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

Accepted Answer

While it may be tempting to proceed with testing, an unlabeled specimen is a serious issue that could lead to incorrect results, incorrect treatment, or even potential harm to the patient. The correct protocol is to not proceed with the test and notify the supervisor immediately. The supervisor can then investigate the issue and take appropriate action to ensure patient safety.

Question 14

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 15

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

Accepted Answer

Even though the test is FDA-approved, laboratories must validate its performance in their specific setting to ensure accuracy and reliability with their equipment and personnel.

Question 16

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 17

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 the organization that provides oversight and governs the use of radioactive materials in the clinical laboratory. The National Fire Protection Association (NFPA) sets safety standards for facilities that use radioactive materials, but does not regulate their use. The Clinical Laboratory Improvement Amendments (CLIA) regulate the quality and accuracy of laboratory testing, but do not specifically address the use of radioactive materials. The American Society for Clinical Laboratory Science is a professional organization for laboratory scientists and does not have regulatory authority.

Question 18

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 refrigerated for two days, which may lead to degradation of viral RNA, resulting in inaccurate viral load results. As a result, the best option would be to request a blood redraw.

Question 19

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 20

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

Accepted Answer

Checking the temperature of a refrigerator used to store patient specimens and reagents should be done daily in order to ensure that the temperature remains consistent and within the appropriate range for the specific items being stored. This helps to prevent spoilage, degradation, and potential harm to patients from compromised specimens or reagents.

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