Medical Technology Licensure Examination (MTLE) Practice Exam

What does systematic error in laboratory testing typically affect?

1. Random variability in results

2. Accuracy of measurements

3. Precision of laboratory methods

4. External quality control outcomes

The correct answer is: Accuracy of measurements

Systematic error in laboratory testing refers to consistent, repeatable errors that can skew results away from the true value. This type of error typically affects the accuracy of measurements. When systematic errors are present, the results obtained from tests are consistently higher or lower than the actual or expected values, leading to inaccurate assessment of a patient's condition or laboratory outcome. In contrast, random variability, which is characterized by unpredictable fluctuations in test results, does not stem from systematic errors. Precision focuses on the reproducibility of results upon repeated measurements; systematic error can lead to a precise set of results that are still inaccurate regarding true values, but it does not affect how closely those results can be repeated. External quality control outcomes relate to the performance of laboratories in comparison to established standards, which can be influenced by systematic error but do not define its nature. Systematic error is primarily tied to accuracy, making it a critical aspect when ensuring the reliability and credibility of laboratory test results.