It is very important that a proper specimen be submitted for testing. Be sure that the correct amount of blood is drawn into each vacuum tube. Improper volume can negatively affect test results. Tubes must be allowed to fill completely, on their own. Do not force additional blood into a full tube.

All blood specimens must be identified with the patient's full name (first and last), date of birth, collection date, and test(s) requested.

Blood tests are performed on serum, plasma, or whole blood. The following is a brief description of each specimen type and instructions to process them properly.

Serum

Serum is the liquid portion of the blood obtained after a serum sample tube has been allowed to clot and is centrifuged. The serum tube may or may not contain a separator gel. The tubes that contain separator gel are commonly called Serum Separator Tubes (SST®). For those tests requiring serum, please use the following procedure:

  • Use a tube with no anticoagulant (i.e. red-top tube, marbled-top tube or SST®).
  • Invert the tube 5 or 6 times after drawing to hasten the clotting process. Do not shake the tube. Shaking may cause hemolysis and result in specimen rejection.
  • Allow the specimen to clot in an upright position for 30 minutes, then centrifuge for 10-15 minutes at 2500-3000 RPM.
  • Serum must be removed from the clot within 45-60 minutes after collection. Transfer the required amount of serum to a plastic transfer tube and cap securely. When removing the serum, be sure not to aspirate any blood cells. If the blood was collected in a SST®, transferring the serum into a plastic transfer tube after centrifugation is not necessary.
  • Please label the plastic transfer tube with the patient's full name (first and last), date of birth, collection date, and the requested test(s).

 

Plasma

Plasma is the liquid portion of the blood obtained after centrifuging specimens collected in tubes containing an anticoagulant. When plasma is required for an assay, use the following procedure:

  • Determine the tube type required to obtain the appropriate plasma sample.
  • Tubes containing anticoagulants should always be filled completely and gently inverted at least 10 times immediately after drawing to assure proper mixing. Do not shake the tubes. Shaking may cause hemolysis and result in specimen rejection.
  • The tubes should be centrifuged for 10 minutes at 2500-3000 RPM. After centrifugation, place the plasma in a plastic transfer tube and cap securely. When you are removing the plasma, be careful not to aspirate any blood cells.
  • Please label the transfer tube with the patient's full name (first and last), date of birth, collection date, requested test(s), and the type of anticoagulant used.

 

Whole Blood

Whole blood is obtained when blood is drawn into a tube containing an anticoagulant. The tube is mixed thoroughly and is not centrifuged.
When whole blood is the required specimen, please use the following procedure:

  • Determine the tube type needed and the required volume.
  • The tube must be filled completely and gently inverted at least 10 times immediately after drawing. Do not shake the tube. Shaking may cause hemolysis and result in specimen rejection.
  • Label the tube with the patient's full name (first and last), date of birth, collection date, and the requested test(s).