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Core Lab Specimens

Serum 
Holy Cross Health recommends the use of serum separator tube (gold top) whenever the specimen requirement is SERUM. After the tube is filled, place the specimen tube in an upright position and allow the blood to clot at room temperature for 20 to 30 minutes. Then centrifuge the tube for at least 15 minutes at 2200-2500 rpm. The specimen may be removed from the centrifuge and placed directly in a specimen transport bag with any necessary forms. Serum should never be frozen in a gel barrier tube.

Whole Blood and Plasma 
When whole blood is required for analysis, always collect blood in the tube containing the appropriate anticoagulant or preservative as specified in the specimen requirement section of this test directory. Once the blood has been collected, gently invert the tube five or six times to thoroughly mix the whole blood with the preservative. Unless otherwise instructed, the entire tube should be placed in the transport bag with the requisition.

If plasma is requested, centrifuge the whole blood at 2200-2500 rpm, remove the stopper, and gently pipette the plasma to a transfer tube without disturbing the cell layer. Never freeze whole blood unless specifically instructed to do so.

Urine 
Collect urine for routine analysis in an appropriate urine cup. Whenever possible, the patient’s first morning specimen, collected by the mid-stream technique, is preferred. Refrigerate the urine specimen to preserve the urine composition and specimen integrity.

View vacutainers for urine collection

24-Hour Urine 
Time specimen collection to insure the specimen is delivered to the laboratory within one day after completion of the 24-hour urine collection. Give the patient a clean, properly labeled, collection container containing the appropriate preservative listed in the specimen requirement section of this test directory. Warn patients when containers have potentially harmful preservatives added (i.e., HCL). Submit an aliquot of the total collection with the total volume noted on the requisition. Also note the patient’s height and weight.

Procedure: 

  • Discard the first morning specimen (Day 1)
  • Label container with the beginning and end time, name, date of birth, height, and weight.
  • Collect all specimens during the remainder of the day and evening. Refrigerate all specimens during the remainder of the day and evening.
  • Collect the first morning specimen (Day 2).
  • Stop collection after the first morning specimen.

Urine Culture
Collect urine specimens in sterile containers using the mid-stream technique. Refrigerate specimens until they are delivered to the laboratory.

Instructions for Female Patients 
Instructions for Male Patients 
Instructions for Infants and Children