Specimen Processing

Principle

To provide guidelines for the processing of specimens collected at Patient Service Centers (PSC), Physician Offices, and other areas outside of the Main Laboratory. Most specimens must be analyzed, centrifuged, or separated from the cells within 2 hours of collection.

Equipment, Reagents, Supplies and Quality Control Material

1. Centrifuge
2. Pipette
3. Greiner Bio-One VACUETTE® plastic vacutainer tubes: Blue, Red/Yellow, Red/Black, Green/Yellow, Lavender-4ml, Lavender-6ml, Pink – 6 ml (Blood Bank)
4. S/P Brand Filter 10.25 mm x 4
5. Blue polypropylene micro-centrifuge tube or 12x75 cloudy polypropylene tube
6. Refrigerator
7. Freezer
8. DyNACHILL

Procedure

1. Temperature Definitions
   
   Room Temperature: 23-29 ° C
   Refrigerator Temperature: 2-8 ° C
   Freezer Temperature: -18 to -23 ° C
   
   Refrigerators and Freezers used for reagent and specimen storage must have temperatures recorded daily.
   
   
2. Collection
   
   Refer to the Basic Venipuncture Procedure, Blood Collection Vascular Access Devices, and/or Fingerstick Skin Puncture Procedure, for specific collection guidelines.
   
   Call Covenant HealthCare Laboratory Customer Service (989.583.6743) with any questions about collection, processing, or transport of specimens.
   
   
3. Processing
   
   Specimens are to remain capped during centrifugation and storage.
   
   
   1. Coagulation Specimens (Blue Top Tubes)
      1. Must be separated from cells within 2 hours of collection
         • Coagulation tests are performed on platelet-poor plasma (less than 10,000/cumm). This can be usually be obtained by centrifugation at 1600-2000 g (3000 rpm) for 10-15 minutes, or centrifugation at 4440 g (7200 rpm) for 3 minutes.
         • Use S/P Brand Filter to separate plasma from cells
         • Gently pour or pipette into a blue polypropylene micro-centrifuge tube or 12x75 cloudy polypropylene tube
      2. Refrigerate if pickup/delivery will be within 4 hours of collection; freeze if pickup/delivery will be greater than 4 hours.
      3. Refer to Processing Off-Site Coag Specimens for a more complete description.
         
         
   2. Chemistry Specimens
      
      Green/Yellow Top Tubes
      1. Most tests require separation from cells within 2 hours of collection
      2. Centrifuge 7-15 minutes at 3000-3200 rpms
      3. Most tests require refrigeration until pickup/delivery
      
      Red/Yellow and Red/Black Top Tubes
      1. Allow to clot at room temperature for 30 minutes prior to centrifugation
      2. Centrifuge 7-15 minutes at 3000-3200 rpms
      3. Carefully pipette serum from Red/Black tubes into a transport tube
      4. Red/Yellow – transport gel separated specimen in original tube
      5. Most tests require refrigeration until pickup/delivery
         
         
   3. Hematology Specimens (Lavender Top Tubes – 4 ml collection)
      1. Sedimentation Rates (ESR): Refrigerate if pickup/delivery to occur greater than 4 hours after collection
      2. Most other tests (unless otherwise stated): Store at Room Temperature before and during transport.
         
         
   4. Specimens for B-type Natriuretic Peptide (BNP) (Lavender Top Tube – 6 ml collection)
      1. Refrigerate whole blood before and during transport
      
      
      
   5. Blood Bank Specimens (Pink Top Tubes)
      1. Refer to Blood Bank Patient Identification and Practices
      2. Refrigerate before and during transport.

Limitations

1. Each individual laboratory test has its own specific collection, processing, and transporting requirements. Any questions should be referred to Covenant HealthCare Laboratory Customer Service at 989.583.6743.
2. Centrifugation times vary with centrifuges. Exact times and speeds should be determined per centrifuge and verified quarterly.

Precautions

1. Practice Standard Precautions. Use gloves, gowns, eye protection, other personal protective equipment, and engineering controls to protect from potential exposure to bloodborne pathogens.
2. Transferring a sample collected using syringe and needle to a tube is not recommended. Additional manipulation of sharps such as hollow bore needles increases the potential for needlestick injury.
3. Transferring a sample from syringe to an evacuated tube using non-sharps devices should be performed with caution: Do not depress the syringe plunger during transfer to avoid splatter and potential exposure. Do not overfill or under fill the tubes. Evacuated tubes are designed to draw the volume indicated. Filling is complete when vacuum no longer continues to draw.

References

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