Architect Total T4 MasterCheck; a single (specified) analyte control (assayed and unassayed); list 6C49-05 Intended for use in the verification of sensitivity, calibration linearity, and reportable range on the Abbott ARCHITECT i System. Abbott Laboratories, Abbott Park, IL 60064

Testing material becomes unstable at the recommeded storage temperature. Some of the Architect Free T4 MasterCheck and Total T4 MasterCheck lots are not stable at the recommended storage condition of 2 to 8 degrees Celsius through expiration dating. These lots may exceed the suggested tolerance limits listed in the Reportable Range/Calibration Verification section in Appendix B of the Architect

Abbott sent a Product Recall letter dated 2/27/08, to all customers who received the affected product lots, informing them that the storage conditions are being changed to -10 degrees C or colder for all lots of material manufactured after lot numbers 82130M and 84110M until the cause has been determined and a corrective action has been implemented. All new shipments will contain additional instructions indicating that the ARCHITECT Free T4 and Total T4 MasterChecks are to be stored frozen until first use. Customers were requested to check their inventory for lot numbers 82130M and 84110M, discontinue use of the lots and destroy any remaining inventory. For lots 82140M, 82150M and 84120M, if they know the date the lot was received or the date it was thawed, they may continue to use lots if they have been stored at 2 to 8 degrees C unopened for less than 60 days. If the material has been stored at 2 to 8 degrees C for greater than 60 days or they do not know the number of days it has been thawed, they were instructed to discard the material. They were requested to forward a copy of the letter to any laboratory to whom they may have forwarded the kits. Any questions were directed to Abbott Customer Support at 1-877-4ABBOTT in the U.S. Customers outside of the U.S., were requested to contact their local customer support representative.