How have the tolerances given for SpecCheck Secondary Gel Standards been determined?

Document ID

Document ID TE7723

Published Date

Published Date 09/12/2019
Question
How have the tolerances given for SpecCheck Secondary Gel Standards been determined?
Summary
SpecCheck Secondary Gel Standards tolerances
Answer
SpecCheck secondary gel standards are used to monitor change in instrument performance only after the parameter/instrument calibration has been verified with chemical standards and specific lots of reagents being used. They are also used to detect any major instrument performance deficiencies upon initial receipt of a new instrument. 

The nominal value for each standard is set at the time of SpecCheck production. The nominal value varies between lots of SpecChecks. The nominal value is the average value determined by measuring a specified number of each standard. The number that is measured and averaged is determined by the lot production size. The standards are targeted to cover low, mid and high concentration values over the calibration range of the parameter being checked.

The specification range was determined at the time of the product origin. It is based on the average scatter obtained on ten different standard gels plus the scatter obtained from reading the standards on three different instruments of each different instrument platform. The range tolerance is then set to cover the range of values that could be expected to be obtained from properly operating instruments, but have slightly different response to the plastic gel medium due to optical properties of the gels. The specification range does not change between lots of SpecCheck standards. These differences are due to the plastic and are not likely to be observed in aqueous samples. Any instrument reading outside the given tolerance range indicates a potential problem with the instrument and technical support should be contacted.

The specific response to each instrument is determined on the SpecChecks and noted on the Record of Performance Verification included with each kit. These values are then specific to that instrument and lot of standards. Variations are then tracked from that initial value.