Specimen Collection & Preparation

Collection instructions for a specific test or profile are linked as PDF files in the Test Menu.

Serum is obtained from clotted blood that has not been mixed with an anticoagulant (chemical that prevents clotting). Serum is usually collected in serum separator tubes.

Serum Preparation Procedures

1. Label all collection tubes with patient’s full name, date of birth, and date of collection using a permanent marker.
2. Draw a sufficient amount of blood to yield the required serum volume. The 10 ml gel-barrier red and gray (tiger) top serum separator tube will yield approximately 4 ml serum after clotting and centrifuging.
3. Place collection tube upright in rack and allow blood to clot at room temperature (no longer than 30 minutes).
4. When clot has formed, centrifuge tube for 10 to 15 minutes. Caution: Prolonged centrifuging may cause hemolysis. Be sure to use a balance tube of the same size with an equivalent volume of water. The tube stoppers must remain on.
5. Turn the centrifuge off and let it come to a complete stop without stopping it with your hand or brake. Remove tubes carefully without disturbing the red cells at the bottom.
6. Holding the tube upright, carefully remove the stopper. Transfer serum from top of tube to a transfer tube with a disposable pipette. Do not disturb the cell layer or allow any cells into the pipette. If cells are disturbed, re-centrifuge specimen. Do not pour the serum or invert serum separator tube.
7. See kit instructions for storage instructions.

 

Common Serum Preparation Errors

• Failure to separate serum from red cells within 30 to 45 minutes of venipuncture
• Hemolysis (red blood cells damaged and intracellular components spilled into serum; hemolyzed serum is pink or red and not the normal clear straw color)

Plasma

Plasma is obtained from blood that has been mixed with an anticoagulant already in the collection tube, and therefore, has not clotted. In many cases, this is a lavender top EDTA tube. This mixed blood is centrifuged, yielding plasma.

Plasma Preparation Procedures

1. Always use the appropriate vacuum tube for tests requiring a special anticoagulant or preservative.
2. Label all collection tubes with patient’s full name, date of birth, and date of collection using a permanent marker.
3. Draw a sufficient amount of blood to yield the required plasma volume.
4. Gently mix the blood by inverting tube six to ten times immediately after collection.
5. Centrifuge immediately for 10 to 15 minutes.
6. Remove tubes carefully without disturbing the red cells at the bottom.
7. Carefully remove the stopper and pipette off the plasma from cells using a disposable pipette.
8. Transfer plasma to a transfer tube. If cells are disturbed, re-centrifuge specimens.

Common Plasma Preparation Errors

• Failure to separate plasma from cells within 30 to 45 minutes of venipuncture
• Hemolysis or damage to red blood cells

 

Whole Blood

Whole blood is blood that has been mixed with an anticoagulant already in the collection tube, and therefore has not clotted. In most cases, this is a royal-blue top Na-EDTA tube, trace mineral-free tube.

Whole Blood Preparation Procedures

1. Write patient name, date of birth, and date of collection on royal-blue top, Na-EDTA, trace mineral-free tube or green top Na-heparin tube using a permanent marker.
2. Draw blood into tube.
3. To process, invert tube gently 10 to 15 times immediately after draw.
4. Leave tube at room temperature.
5. Do not centrifuge or transfer.

Common Whole Blood Preparation Errors

• Failure to invert tube 10 to 15 times to mix anticoagulant immediately after venipunture.
• Failure to leave specimen at room temperature.

 

Blood Spot

Blood spot specimens are collected by carefully applying a few drops of blood, freshly drawn by fingerstick with a lancet from adults or children or by heel stick with a lancet from infants. The blood is collected onto a specially manufactured absorbent filter paper card. The blood is allowed to thoroughly saturate the card and is air-dried overnight, up to 24 hours.

Blood Spot Preparation Procedures

1. Write the patient’s full name, date of birth, and date of collection on collection card using a permanent marker.
2. Wipe the tip of the ring or middle finger with an alcohol swab.
3. Read test kit instructions on how to properly use the lancet.
4. Firmly grasp the lower portion of the finger and press the end of the lancet to fingertip and release.
5. Milking the finger, lightly touch the blood drop to the collection card filling the required number of circles completely. Fill each circle completely with blood.
6. Saturate blood through the collection card so that the circle is uniformly darkened, leaving no white or light areas.
7. Dispose of the lancet in a suitable container. Also dispose of any unused lancets.
8. Allow collection card to completely dry overnight, up to 24 hours.

Common Blood Spot Preparation Errors

• Failure to fully saturate ALL the circles on the collection card.

Pediatric Blood Draw Collection Instructions

Blood draws for patients under 14 years of age may need to be performed in more than one sitting depending on the amount of blood required for the test or profile. Recommended blood draw instructions based on weight can be downloaded here.

Urine specimens are required for many of our tests. It is very important that the specimen collection procedure be followed accurately to yield reliable results. Following the instructions for collection, preparation, and shipping will help us to provide the most accurate test results possible.

Important for Patient to Remember for Urine Collections:

• Do not collect urine during menstruation.
• Urine should be stored per kit instructions to prevent bacterial growth until analysis is performed.

 

24-Hour Urine

The 24-hour urine collection should be collected in a wide-mouth, clean, properly labeled urine container generally provided by the laboratory. It is essential to record the total volume for a 24-hour urine specimen. The transfer tubes provided by the laboratory contain the necessary preservative for handling and shipping.

Important Patient Instructions for 24-hour Specimens:

• The first urine passed in the morning must NOT be collected. Instead, record the time on the container label and that will mark the beginning of the collection period.
• The first urine passed and collected the next morning at exactly the same time as the previous morning will mark the end of the collection period.
• It may be easier to urinate into a smaller, clean container than the large collection container. Nothing besides urine can be added to the containers for accurate results. Do not pour out any preservative (powder or liquid) that may be in a container and handle with caution since it may be caustic.
• It is very important to keep and record the entire volume of urine during the collection period.
• Urine passed during bowel movements must also be collected.
• When the 24-hour period is over, be sure to mix the entire collection thoroughly so the amount you transfer and ship for analysis represents the entire collection.
  

Overnight/First Morning Urine

An overnight urine specimen consists of any voids during the night, as well as the first-morning void, collected in the same clean container. More concentrated than urine collected in the day, it has a higher creatinine level that is used for standardization of the specimen. Drinking large volumes of fluid the day or evening before the collection can dilute the sample and cause the creatinine concentration to be too low. When the creatinine level is too low (<20mg/dl), the sample will need to be resubmitted. To avoid this, it is recommended that patients reduce fluid intake the day prior to specimen collection. This is particularly important for pediatric and elderly patients, who generally have more dilute-urine.

Timed Urine

Whenever a dose of a challenge substance is used and the appearance of the substance or its metabolite in urine is to be determined, the urine must be collected from a specified start time for an exact time interval. The start time is usually the time the dose was taken. Adherence to the interval or hours is important because the reference values are based on the amount of the substance appearing during this interval.

Pediatric Urine Collection Instructions

Pediatric specimens are collected from infants using a collection bag designed for use with a diaper. Pediatric urine collection materials are available for use with the ION Profile, Organix Profile, and Porphyrins Profile. Download Pediatric Urine Collection Instructions here.

Common Urine Specimen Errors

• Failure to provide a complete 24-hour collection or timed specimen
• Failure to add the proper preservative to urine collection container prior to specimen collection
• Failure to provide total urine volume
• Urine that is too dilute for accurate measurement (creatinine too low)
• Failure to label specimens with two unique identifiers (patient's name and date of birth) using a permanent marker

Saliva is collected with a cotton salivette that comes in a tube. To collect saliva, the patient can either chew on the salivette or allow it to saturate inside the mouth for 30 to 45 seconds. The cotton is then returned to the tube and sent to the laboratory.

Important Patient Instructions for Saliva Specimens

• Label all specimens with two unique identifiers (patient's name and date of birth) using a permanent marker.
• Label with date of collection.

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GI Effects Stool Profiles offer stool analysis with a single collection.

Important Patient Preparation for Stool Collection:

• Refrain from taking digestive enzymes, antacids, and aspirin for two days prior to specimen collection, unless otherwise instructed by your healthcare provider.
• Finish taking antifungal or antibiotic medications and wait three days before collection.
• Never discontinue prescription medications without consulting your healthcare provider first
• Do NOT rinse tubes or pour out preservative.
• Do NOT overfill tubes. Please add specimen only to the "fill line".

Stool Preparation Procedures

1. Write the patient's full name, date of birth, and date of collection on both vials using a permanent marker.
2. Put on the disposable gloves
3. Collect your stool specimen using enclosed collection container
4. Remove cap on the orange cap vial and, using the attached spoon, transfer stool specimen into the vial. Take multiple portions from different areas of the collection container. Fill the vial to the fill line. DO NOT OVERFILL. Screw the cap on tightly.
5. Repeat with pink cap vial.
6. Shake the pink and orange cap vials vigorously for approximately 30 seconds to mix the stool specimen with the preservative in the vial.
7. Dispose of the remaining specimen and the collection container appropriately.
8. Place the vials and the orange absorbent pad into the biohazard bag and seal the bag.
9. Place the biohazard bag with the vials into the refrigerator until you are ready to ship.

Safety and Disposal Considerations in Specimen Collection

In all settings where specimens are collected and prepared for testing, laboratory and healthcare personnel should follow current recommended sterile techniques, including precautions regarding the use of needles and other sterile equipment as well as guidelines for the responsible disposal of all biological material and contaminated specimen collection supplies. Guidelines for the proper use and disposal of needles and other biohazard materials are on the Centers for Disease Control and Prevention web site.