The investigation has determined that a lower than expected vitros tsh result was obtained from a patent sample when tested on a vitros 5600 integrated system using reagent lot 6680 when compared to results obtained from a non-vitros system for the same sample.The definitive assignable cause for the lower than expected vitros tsh result was a discrepant tsh baseline concentration associated with vitros hsda lot 2190.The baseline tsh concentration is included on the assay data disk (add)/mag card and when an on-board tsh dilution is performed, the baseline tsh concentration is subtracted out before the final result is reported.An investigation performed by ortho (complaint investigation (b)(4)) determined the baseline tsh concentration for hsda lot 2190 was incorrectly defined in the add/mag card.Correct: hsda baseline tsh concentration as per certificate of analysis: 0.112 miu/l incorrect: hsda baseline tsh concentration as defined on the add: 112 miu/l the incorrect hsda value (112 miu/l versus 0.112 miu/l) impacts the calculated tsh concentration leading to negatively biased tsh results when a sample is diluted.However, it would not be expected that this issue would go undetected, as the customer will be aware the undiluted result was above the vitros tsh measuring range of 0.015 ¿ 100 miu/l, and the diluted result was within the measuring range, indicating discordant results.Continual tracking and trending of complaints has not identified any signals that would indicate a potential systematic issue with vitros tsh reagent lot 6680.(b)(4).
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