Mixed Deck — All AACC Topics Flashcards

Which of the following best describes a 'delta check' in laboratory quality management?

Answer: A comparison of a patient's current result with their previous result to flag unusual changes

Delta checks compare a patient's current result to prior results to identify clinically implausible changes that may indicate specimen labeling or collection errors.

Which turnaround time (TAT) metric measures the time from when a specimen is received in the laboratory to when the result is reported?

Answer: Laboratory TAT

Laboratory TAT measures the internal processing time from specimen receipt to result reporting, which is directly controllable by laboratory operations.

What does the term 'carry-over' mean in the context of automated analyzer performance?

Answer: Contamination of a sample by residual analyte from a previously analyzed high-concentration sample

Carry-over occurs when residual analyte from a high-concentration specimen contaminates the subsequent specimen, potentially causing falsely elevated results.

Which laboratory test is the standard for monitoring unfractionated heparin (UFH) therapy?

Answer: Activated partial thromboplastin time (aPTT)

UFH is monitored with aPTT because heparin potentiates antithrombin III inhibition of intrinsic pathway factors, prolonging the aPTT; therapeutic range is typically 1.5–2.5× control.

What is the purpose of a control sample?

Answer: Verify test performance

A control sample is a material with a known, stable concentration of an analyte that is run alongside patient samples during testing. Its purpose is to verify the accuracy and precision of the analytical method and instrument performance. By comparing the measured value of the control to its known target range, laboratories can confirm that the test system is operating correctly and producing reliable results.

In the evaluation of a microcytic anemia, which set of iron studies distinguishes anemia of chronic disease (ACD) from iron deficiency anemia (IDA)?

Answer: ACD: high ferritin, low TIBC, low serum iron; IDA: low ferritin, high TIBC, low serum iron

ACD shows elevated ferritin (acute-phase reactant), low TIBC (suppressed iron transport), and low serum iron; IDA shows low ferritin (depleted stores), high TIBC, and low serum iron.

According to CLSI standards, what is the maximum recommended time between venipuncture and centrifugation for a serum tube?

Answer: 30 minutes to 1 hour after complete clotting

CLSI recommends centrifugation within 30–60 minutes of collection after complete clot formation to minimize analyte degradation and cellular metabolism effects.

Which competency is MOST essential for professionals working in emergency response & critical care in American Association for Clinical Chemistry?

Answer: Critical thinking combined with practical application of knowledge

Critical thinking allows professionals to apply knowledge effectively in varied situations, leading to better outcomes than rote procedures.

What does a calibration curve help determine?

Answer: Concentration of unknowns

A calibration curve is a fundamental tool in analytical chemistry used to determine the concentration of an unknown sample. It is created by measuring the instrument's response (e.g., absorbance, fluorescence) to a series of solutions with known concentrations of the analyte. By plotting these known concentrations against their corresponding responses, a standard curve is generated, allowing the concentration of an unknown sample to be interpolated from its measured response.

What is the BEST approach to documentation & health records standardization in American Association for Clinical Chemistry?

Answer: Implementing consistent formats, terminology, and processes across the organization

Organization-wide consistency in formats, terminology, and processes ensures data can be shared, compared, and analyzed effectively.

How does ongoing professional development support professional ethics & legal standards in American Association for Clinical Chemistry?

Answer: It keeps professionals informed of evolving standards and best practices

Ongoing professional development ensures that practitioners stay current with evolving regulations, standards, and best practices in their field.

In mass spectrometry-based clinical assays (LC-MS/MS), what is the role of the internal standard?

Answer: To correct for variations in sample preparation, ionization efficiency, and instrument response

An internal standard, typically a stable isotope-labeled analog of the analyte, corrects for matrix effects and procedural variability, improving quantitative accuracy.

How often should calibration be performed?

Answer: As specified by manufacturer or regulations

Calibration is essential for ensuring the accuracy of laboratory instruments and must be performed regularly. The frequency of calibration is typically specified by the instrument manufacturer, regulatory agencies (like CLIA), or the laboratory's own validated protocols. It is crucial to adhere to these guidelines to maintain the reliability of test results and ensure that instruments are consistently providing accurate measurements.

In flow cytometry used in clinical laboratories, what physical property is measured by the side scatter (SSC) signal?

Answer: Cell granularity and internal complexity

Side scatter reflects light at approximately 90° and correlates with the internal complexity and granularity of a cell.

Which type of analyzer configuration processes one test at a time on a single patient sample?

Answer: Discrete analyzer

Discrete analyzers process individual reaction vessels for each test-patient combination, preventing carryover between tests on different patients.

Which patient education & health promotion technique is MOST appropriate when delivering complex information in American Association for Clinical Chemistry?

Answer: Breaking information into manageable segments and confirming understanding

Breaking information into manageable segments and checking understanding ensures comprehension and retention of complex material.

When should clinical assessment & patient care be conducted in American Association for Clinical Chemistry?

Answer: At regular intervals and whenever significant changes occur

Regular assessments combined with trigger-based reviews ensure ongoing monitoring while capturing the impact of significant changes.

What is the purpose of a Levy-Jennings chart in laboratory instrumentation monitoring?

Answer: To graphically track QC values and detect systematic or random error trends

Levy-Jennings charts plot sequential QC results against time, with control limits at ±2SD and ±3SD to visualize shifts, trends, and random errors.

Why is quality control important in clinical chemistry labs?

Answer: To guarantee accurate results

Quality control (QC) is paramount in clinical chemistry labs to ensure the reliability and accuracy of test results. By regularly running control samples with known values, laboratories can monitor the performance of their analytical methods and instruments. This process helps detect errors, identify trends, and ensure that patient results are consistently precise and accurate, leading to correct diagnoses and appropriate patient care.

What type of interference is caused by lipemia in photometric assays?

Answer: Optical interference due to light scattering by lipid particles

Suspended lipid particles in lipemic samples scatter light, increasing apparent absorbance and causing falsely elevated results in photometric methods.