Lab Handling

If the testing is not completed within 24 hours for PT specimens and four hours for APTT and other assay specimens, plasma should be removed from the cells and frozen at –20°C for up to two Weeks or –70°C for up to six months. A frost-free freezer should not be used. Frozen plasma samples should be rapidly thawed at 37°C while gently mixing and tested immediately; if testing cannot be performed immediately, the sample may be held for a maximum of two hours at 4°C until tested. The APTT may be affected on specimens which have been frozen. Completed samples will be saved and discarded after 48hr per CAP.