At Phoenix Lab, we pride ourselves on consistently delivering highly accurate, reliable results on all of your laboratory testing. A big part of providing this service is ensuring that all of our samples are handled from collection to arrival at the lab. A variety of issues can plague samples, from the collection process itself to seasonal temperatures.
- Please examine all specimen collection and transportation supplies to make sure they are not expired.
- When collecting the sample, select the appropriate size syringe and needle to ensure enough sample is collected and to help avoid hemolysis. When possible, use a 20g needle or larger.
- Make sure you have the proper tubes available. Additives that preserve a sample for one type of test may actually interfere for a different test (ex: EDTA will cause chemistry results to be very inaccurate).
- Select the proper size tubes for the anticipated volume – use smaller tubes for smaller patients. Tubes that are too large can result in inaccurate results due to dilution or “QNS” (quantity not sufficient) errors.
- Ensure your patient is properly prepared for the collection. Fasting is helpful to avoid lipemia. Medications should be administered at the proper time before or during the testing process.
Immediately after collection
One of easiest, yet most important things immediately post collection is proper labeling of the sample. All samples should be labeled with the first and last name of the patient. Labeling date and time of collection is especially important for tests like pre- and post-bile acids, ACTH stim tests, or dex suppression tests.
Other post-collection considerations include:
- Immediately and gently, invert the tube 5-10 times to mix the sample with any additives.
- Allow serum samples to clot for a minimum of 15 minutes before centrifugation.
- Centrifuge and separate serum or plasma from red cells within 2 hours of collection. Red cells can falsely decrease glucose and falsely elevate K+ if not separated quickly.
- Serum or plasma samples with no gel separator should be transferred to a different tube and labeled “serum” or “plasma.”
The most common urine collection considerations:
- Mark the method of collection – free catch, catheter, cystocentesis
- Store specimens in a urine tube or a “no additive” clear red top tube. Secure lids to avoid leakage.
- Store in a cool place, such as a refrigerator.
Outdoor Specimen Lockboxes
Ideally, samples should stay indoors, stored at the proper temperature, until collected by the courier. Evening sample pickups after closing may make this impossible, and samples may be placed outside in a lockbox until the courier arrives. Lockboxes should be insulated with Styrofoam, should close properly, and should not have any rust/damage. If your lockbox needs repair, please notify Phoenix Lab.
For clients whose specimen lockboxes must be placed outdoors, adding a frozen gel pack to the lockbox during warmer weather will help provide a moderate temperature inside the lockbox until specimens are collected by your Phoenix courier. Gel packs should be prepared for use by placing them in a freezer for four hours or longer. They should be frozen solid prior to being placed in the lockbox, and they should be frozen solid before each use, even though they may be used with specimens that are not frozen.
If it is not possible to avoid placing the specimen lockbox in direct sunlight, add 20°F to the temperatures listed above to determine how many frozen gel packs to use.
When temperatures are below freezing, a thawed (room temperature) gel pack in the lock box can help prevent sample freezing.
Written by Dr. Kimberly Pattullo, DVM, MvetSc, DACVP