Beckman Coulter UniCel DxC 600, Инструкция по эксплуатации

Страница: 423 / 498

A13914AF
12-7
Troubleshooting Calibration and Result Errors
Linear Calibration
12
Linear Calibration
Overview
For all linear photometric chemistries, the UniCel DxC sets calibration based on two or four
calibrator replicates.
•
For calibrations using four replicates, the instrument will determine and discard the highest
and lowest values of the four replicates. The remaining two values are called the usable
calibrator replicates. Only the two usable replicates will be used for the calibration calculations.
The average value of the usable calibrator replicates is used to determine the calibration factor.
•
For calibrations using only two replicates, the instrument uses the average of both replicates in
determining the calibration factor.
Calibration fails if one or more of the usable replicates is flagged.
Linear calibration chemistries include Endpoint and First Order reactions. For additional
information about linear calibration or for specific calibration equations, refer to CHAPTER 1,
System Description , Endpoint and First-Order Chemistries and Endpoint and First-Order Calibration
Formulas .
Calibration flags that are specific to the linear photometric chemistries, causing the reagent to fail
its calibration, are back-to-back and Calibrator Range (High/Low) errors, and for linear chemistries
that use more than one calibrator, Span.
To view the calibration flag limits for all calibrated chemistries, access View Calibrator Acceptance
Limits in the
Rgts/Cal
screen under
Options
. Calibration flags for any chemistry with loaded
calibration data are available to view and print.
Back-to-Back
• A back-to-back error check is a measure of system precision during calibration.
•
A back-to-back value is the difference between the two usable replicate values. If the back-to-
back limit is exceeded the calibration fails.
•
Limits are either pre-programmed in the system chemistry database or downloaded from disk
before calibration.
Calibrator Range (High/Low)
•
Calibrator Range (High/Low) error check is a measure of reagent performance or accuracy.
• Calibrator ADC values are compared to acceptable ranges for calibrator values. Calibration fails
if the calibrator ADC values fall outside the acceptable calibrator limits.