Laboratory Performance Analysis Quiz
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Questions and Answers

Which term describes the agreement between your value and the ‘true’ value?

  • Specificity
  • Accuracy (correct)
  • Precision
  • Sensitivity

    • Precision refers to the correctness of a single measurement.

    False

    What is the term used to describe the reproducibility of your results?

    Precision

    Accuracy is determined by direct comparison to a __________ value.

    <p>reference</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Accuracy = The agreement with the true value Precision = The reproducibility of results Sensitivity = The ability to correctly identify true positives Specificity = The ability to correctly identify true negatives</p> Signup and view all the answers

    What consequence may arise from a lack of specificity in a test?

    <p>Both A and C</p> Signup and view all the answers

    Poor precision can result from poor quality reagents.

    <p>True</p> Signup and view all the answers

    What is the primary ability of a method that defines its specificity?

    <p>The ability to measure solely the component of interest</p> Signup and view all the answers

    A test's __________ reflects its ability to detect small quantities of a measured component.

    <p>sensitivity</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Precision = The closeness of measurements to each other Accuracy = The closeness of a measurement to the true value Specificity = Ability to measure solely the target component Sensitivity = Ability to detect small quantities of an analyte</p> Signup and view all the answers

    What is a key indicator of precision in measurements?

    <p>The closeness of repeated results</p> Signup and view all the answers

    Intra-assay precision refers to the reproducibility of results within one test run.

    <p>True</p> Signup and view all the answers

    What are the two ways in which precision is assessed?

    <p>Intra-assay precision and inter-assay precision.</p> Signup and view all the answers

    The ideal situation in accuracy and precision is when results are _____ and the mean is close to the ‘true’ value.

    <p>accurate</p> Signup and view all the answers

    Which example describes a situation that is imprecise but still accurate?

    <p>Results are widely spread but the mean is close to the true value.</p> Signup and view all the answers

    Labs can efficiently waste resources on repeat runs if they are not achieving acceptable accuracy.

    <p>False</p> Signup and view all the answers

    What is the significance of having precise test results for a lab?

    <p>It increases confidence in the accuracy of test results and reduces the need for repeat tests.</p> Signup and view all the answers

    Match each term with its definition:

    <p>Accuracy = Closeness of results to the true value Precision = Closeness of repeated measurements Intra-assay Precision = Reproducibility within the same test run Inter-assay Precision = Reproducibility across different test runs</p> Signup and view all the answers

    What does diagnostic sensitivity refer to?

    <p>The ability of a test to detect a given disease or condition</p> Signup and view all the answers

    The mean of a normal distribution is also known as the median.

    <p>True</p> Signup and view all the answers

    What is the purpose of determining diagnostic specificity?

    <p>To correctly identify the absence of a disease.</p> Signup and view all the answers

    The _____ is defined as the square root of the sum of the squared deviations from the mean.

    <p>Standard Deviation</p> Signup and view all the answers

    What does the coefficient of variation indicate?

    <p>The ratio of the standard deviation to the mean</p> Signup and view all the answers

    A high standard deviation indicates that the values are closely clustered around the mean.

    <p>False</p> Signup and view all the answers

    Match the following diagnostic terms with their definitions:

    <p>Sensitivity = Ability to detect positives Specificity = Ability to detect negatives False Positive = Test result indicating disease when none is present False Negative = Test result indicating no disease when it is present</p> Signup and view all the answers

    In a normal distribution, values fall randomly about the _____ value.

    <p>mean</p> Signup and view all the answers

    What does a lower standard deviation indicate about precision?

    <p>More precision</p> Signup and view all the answers

    68% of all results are expected to fall within ± 2 standard deviations from the mean.

    <p>False</p> Signup and view all the answers

    What is the formula for calculating standard deviation?

    <p>SD = sqrt(Σ(xi - x)² / (n - 1))</p> Signup and view all the answers

    The mean result in this example is _____ mmol/L.

    <p>100</p> Signup and view all the answers

    Match the standard deviation range to their corresponding percentages.

    <p>± 1 SD = 68% of results ± 2 SD = 95% of results Mean = 100 mmol/L SD = 1.0 mmol/L</p> Signup and view all the answers

    If the standard deviation is 1.0 mmol/L, what is the range within which 68% of the results fall?

    <p>99 – 101 mmol/L</p> Signup and view all the answers

    Statistically, it is acceptable for 10% of results to fall outside of ± 2 standard deviations from the mean.

    <p>False</p> Signup and view all the answers

    The number of results in this example is _____ .

    <p>100</p> Signup and view all the answers

    Study Notes

    Laboratory Performance Analysis

    • Accuracy refers to how close a measured value is to the true value.
    • Precision describes the reproducibility of measurements, meaning how close repeated measurements are to each other.
      • Within-run precision (intra-assay precision) assesses precision within a single analytical run.
      • Between-run precision (inter-assay precision) assesses precision across different analytical runs.
    • Specificity indicates the ability of a method to measure only the intended analyte, minimizing interference from other substances.
    • Sensitivity refers to the method's ability to detect small quantities of the analyte.

    Common Quality Control Terms

    • Quality Control (QC) involves procedures and processes used to ensure the accuracy and reliability of laboratory results.

    Statistical Concepts for Quality Control

    • Normal Distribution describes the spread of data points around a central average, known as the mean.
    • Standard Deviation (SD) represents the average dispersion of data points from the mean.
      • A lower SD indicates better precision.
    • Coefficient of Variation (CV) is the ratio of the SD to the mean, expressed as a percentage.
      • It provides a standardized measure of precision, regardless of the specific units of measurement.

    Interpreting Statistical Data for Precision

    • Mean ± 1 SD: Approximately 68% of data points fall within one standard deviation of the mean.
    • Mean ± 2 SD: Approximately 95% of data points fall within two standard deviations of the mean.

    Solving Precision and Accuracy Problems

    • Poor accuracy is often caused by calibration issues, which are usually easier to address.
    • Poor precision can have various causes, such as:
      • Poor quality reagents
      • Improperly maintained instruments
      • Inadequate training

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    Related Documents

    Quality Control Definitions PDF

    Description

    Test your knowledge on key concepts related to laboratory performance analysis, including accuracy, precision, specificity, and sensitivity. This quiz also covers essential quality control terms and statistical concepts fundamental for reliable lab results.

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