Hematology Quality Control

The Levey-Jennings Diagram displays scattered values for inaccurate and imprecise data.

Expired controls or reagents can cause a trend in the measurements.

A sudden shift in values indicates a change in the instrument's calibration.

Imprecise data is characterized by values that are far from the target value.

Verifying the instrument's calibration is part of preventative maintenance.

A trend in the measurements is always caused by an instrument drift.

Accurate data is characterized by values that are close to the target value.

A shift in values can be caused by a change in the laboratory environment.

Hematology analyzers do not require quality control to ensure valid patient results.

Instrument manufacturers typically supply hematology controls with only one level designed to resemble patient samples.

Quality control in hematology is only necessary for accreditation purposes.

The main purpose of internal QC is to monitor the analytical process only.

Accuracy and precision are interchangeable terms in hematology controls.

Hematology controls cover only a few blood parameters.

Quality control samples are only used for five-part differential analysis.

Internal QC is not necessary for laboratories to establish their own QC program.

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

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

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 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

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