What is the accuracy of the Quantab® Chloride titration test strips?

Document ID

Document ID TE12484

Published Date

Published Date 04/16/2020
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Question
What is the accuracy of the Quantab® Chloride titration test strips?
Summary
Statement of accuracy for Quantab® Chloride titration test strips.
Answer
The QA personnel use a well-documented procedure for testing each lot of Quantab® Chloride titrator strips. First a calibration curve is constructed by developing ten strips for each of either five or six levels of Sodium Chloride concentration (more information on this can be found here: How are the Chloride Quantab® test strips calibrated?). ) Data for each level must show a standard deviation of 0.2 Quantab Units (2% of the scale of 10 on the titrator) or less.

New test solutions are prepared for the testing of four accuracy levels of sodium chloride. Each accuracy level is tested with nine strips selected at random from the lot. The average of the nine values must be within 10% of the standard value (from the calibration curve). If this test fails at a particular Sodium Chloride level, six strips are sampled from each of six locations within the lot, and all 36 strips are used to test the failing level. The aver of the 36 results must be within 10% of the standard value.

The purpose of these QA test is to be sure that lots failing either of these tests do not ship. There is also a brief testing step for the chemically impregnated pater before it is laminated and made into titrator test strips. Thus the Quantab® Chloride titrator test strips are certified to have an accuracy of ±10%.  Precision could be inferred from the required standard deviation for each Sodium Chloride level of the calibration data (0.20 Quantab Units). The percent Sodium Chloride vs Quantab Units curve is not linear, and a given variation in Quantab Units corresponds to a greater variation in percent Sodium Chloride at the high end of the range compared to the lower part of the range. From the appearance of the plot, the precision expressed as a fraction (standard deviation over percent Sodium Chloride value) seems not to vary much from ~±10%. There are additional specification ensuring that the Quantab peak has an acceptable appearance and that the lamination is of good quality.

This information is applicable for Product # 2744940 and 2751340

 
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