Specimen Collection and Processing

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Specimen Collection and Processing

The specimen collection and processing department is where in-and out-patient laboratory specimens are received, accessioned, evaluated for adequacy and urgency, and prepared for testing. Most blood and other specimens are not collected in the clinical laboratory but in various hospital wards, ICUs, emergency departments, and other in- and out-patient locations. However, most clinical laboratories within hospitals do have a phlebotomy area and urine collection area for when the occasional out-patient comes directly to the laboratory.
The specimen collection and processing department is staffed by MLTs, phlebotomists, and MLAs. In some instances, MLSs are also present, generally as supervisors. When a specimen is received in the laboratory, the staff are responsible for accessioning the specimen.
The hospital and laboratory staff collect most blood specimens from patients using phlebotomy. Also known as venipuncture, phlebotomy is performed by applying a tourniquet and then inserting a small needle into an appropriate vein in the antecubital fossa, forearm, or the back of the hand. The blood is then drawn into vacuum blood collection tubes that contain various additives, such as anticoagulants or clot activators, appropriate for specific tests. The tubes are distinguished by a universal color-coded top system:
  • Light Blue-top: coagulation testing, including prothrombin time and aPTT
  • Lavender-top: hematology testing, including the complete blood count (CBC)
  • Speckle-top: also known as a serum separator tube, chemistry testing, including the lipid panel
  • Red-top: chemistry, immunology, and transfusion services testing, including hepatitis and HIV tests
  • Green-top: chemistry testing, including the basic metabolic panel (BMP)
  • Gold-top: chemistry and immunology and serology testing
  • Pink-top: transfusion services testing, including ABO and Rh blood typing
The staff may also collect urine from out-patients if required for testing. Most urine specimens are known as random specimens, since there is not a designated time of collection. Other urine tests may require specimens to be collected at specific times, such as first in the morning.
After accessioning specimens and confirming their identities and integrity, the staff may perform additional processing, such as centrifugation. Once specimens are fully prepared, they are sent to the appropriate laboratory departments for testing, sometimes by conveyor system.

An MLT practicing phlebotomy on a fellow MLT, supervised by an MLS.
Evacuated tubes with lavender (EDTA), dark green (sodium heparin), and blue
(sodium citrate) tops.