Some samples are disposed of once the sample has been tested. Due to the nature of those samples, they can not be retested. Other samples are stored for up to one month after their report date. Please contact the laboratory, as soon as possible, if you wish a sample to be retested or stored for a longer period of time. We would be happy to retest those samples, however if the repeat result confirms the first result, the client will be charged for the second test.