Serum or plasma specimens need to be frozen only if specifically stated in the specimen requirement. However, in these cases, it is essential to freeze the specimen as soon as it is separated from the cells. Always freeze specimens in plastic tubes unless specifically instructed otherwise.
Lay the tube at a 45° angle to avoid tube breakage caused by expansion during freezing. Do not freeze plastic Serum Separator Tubes. An exception is a specimen submitted in a PPT tube; the plasma can be frozen and transported in the original tube.
Extreme cold may cause ordinary plastic labels to become brittle and detach from the specimen tube. Use clear tape to secure label to specimen transport tube.
Note: If more than one test is requested on a frozen specimen, split the sample prior to freezing. Use a separate test requisition when submitting a frozen specimen; frozen and non-frozen specimens must not be submitted on the same test requisition. Indicate on specimen container and test requisition if specimen is plasma or serum.
If more than one test is ordered on a single frozen sample, we will call you to choose which test you want performed before testing can proceed.