Hematology Analyzer Quality Control

Hematology controls are only used to assess the precision of erythrocyte sedimentation analyzers.

Instrument manufacturers usually supply hematology controls with five levels.

Quality control in hematology is important to ensure the consistent reliability of sample results.

The main purpose of internal QC is to detect errors due to operator performance only.

Accuracy and precision are the same concept in hematology controls.

Hematology controls are only used to monitor long-term test performance.

A quality control program is not obligatory in a laboratory setting.

Hematology controls guarantee both accuracy and precision of patient results.

Accurate data is always precise.

A trend in a Levey-Jennings diagram is always caused by a drift of the instrument.

A shift in the Levey-Jennings diagram indicates a sudden change in the system.

Imprecision is the same as inaccuracy.

The ideal situation is when the individual values are far from the target and have large variations.

The Levey-Jennings diagram shows the mean value over time.

Expired controls or reagents can cause a trend in the Levey-Jennings diagram.

Knowing the root cause of a problem makes it harder to take corrective action.

Importance of Quality Control in Hematology

Hematology controls ensure precise and accurate patient results, meeting accreditation requirements
Daily measurement of quality control samples is obligatory for intra-instrument quality control

Types of Hematology Controls

Controls with assayed values for three-part and five-part differential analysis as well as erythrocyte sedimentation controls are available
They cover multiple blood parameters, including erythrocytes, platelets, granulocytes, lymphocytes, monocytes, hematocrit, hemoglobin, and many more

Purposes of Internal Quality Control (QC)

Monitoring of the analytical process
Detection of errors due to system failure, adverse environmental conditions, or operator performance
Monitoring of long-term test performance
Providing proof of adequate long-term quality level and complying with regulatory requirements

Accuracy and Precision in Hematology Controls

Accuracy refers to the ability to achieve the right result
Precision refers to the ability to achieve the same result over and over again
Four possible scenarios can occur with hematology controls: accurate and precise, not accurate and precise, not accurate but precise, and accurate but not precise

Scenarios of Accuracy and Precision

1. Accurate and Precise

Ideal scenario with accurate and precise values
Levey-Jennings Diagram shows a constant line around the mean

2. Not Accurate and Precise (Trend)

Neither accurate nor precise values
Levey-Jennings curve shows a trend, indicating a drift of the instrument
Possible causes: incorrect use of controls or reagents, expired materials, approaching calibration date, or need for preventative maintenance

3. Not Accurate but Precise (Shift)

Sudden shift in values
Precise measurements but not accurate
Possible causes: part change, reagent lot number change, or environmental changes

4. Accurate but Not Precise (Imprecision)

Accurate mean value but varying measurements
Several conditions can cause imprecision

This quiz assesses knowledge on the importance of quality control in hematology analyzers to ensure accurate patient results and meet accreditation requirements. It covers the role of daily quality control sample measurement and the use of controls supplied by manufacturers.