Beckman Coulter UniCel DxC 600, Instructions For Use Manual

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System Description
Modular Chemistry: Calibration Theory
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Drugs of Abuse Testing (DAT) Chemistries
The Drugs of Abuse Testing (DAT) assays require three levels of calibrators. The calibration
measures the separation between calibrators to measure reagent integrity. The calibration factor
generated is non-functional for sample result calculation.
The cutoff value for each DAT chemistry represents the mean reaction rate of the low calibrator,
reported in mA/min units on patient and control reports. The reaction rate of the samples is
compared to the reaction rate of the low (cutoff) calibrator and reported out as POSITIVE or
NEGATIVE. Cutoff values are stored in memory until the next successful calibration.
Enzyme Verification
Enzyme verification is a means of adjusting enzyme chemistry reporting units to IFCC/DGKCh
methods. This feature is available for ALP, ALT-, AST-, CHE, CK-, GGT and LD. Verification also allows
results to be adjusted for country specific correlation needs.
Verification is similar to calibration except that normalization factors are applied to the sample
result in the form of a slope and offset adjustment, whereas calibration factors would be applied to
the reaction response.
Modular Chemistry: Calibration Theory
Calibration Theory
Modular chemistries are calibrated using two to three levels of calibrator (chemistry dependent).
Four replicates per level are assayed. Data from two middle replicates of each level is used to set the
system response. The highest and lowest replicates are discarded. Error checks are performed on
the two middle replicates to verify successful calibration.
Calibration Error Detection
The analog signals generated by the calibrator measurements are converted to digital form. The
resulting ADC values are compared to pre-programmed back-to-back, span and range limits to
determine the calibration acceptability.
Modular Chemistries (MC)
The UniCel DxC contains seven chemistry modules (see chart below), each of which is used in the
determination of eleven modular chemistries (MC), as follows.