Sample Processing

Sample Handling and Processing

For serum samples, the clot should be removed as quickly as possible (within hours of collection). Although serum separator tubes are convenient, experience suggests samples are prone to have some degree of hemolysis (see "Sample Collection", picture 2) and prolonged clot contact. Simple red top tubes are the best choice for serum collection.

Samples should be centrifuged at 2200 rpm for 20 minutes to remove the clot. Serum can then be drawn off the top and transferred to a new red top tube for submission to the lab.

Picture 1 - Properly balanced samples loaded into centrifuge.

Tubes in centrifuge

Preparing Individual Samples:

- For individual samples, pipet the total amount of serum needed by the lab from the collection tube into a new red top tube.

Preparing Pooled Samples:

- In preparing pooled samples one must be meticulous in precisely measuring equal amounts of serum from each individual to be included in the pooled sample. Depending upon the total number to be included, typically between 100 and 500 microliters (0.1 to 0.5 ml) from each individual are mixed into a new clean test tube (7 to 10 ml capacity). This process is best completed with a micropipettor or a TB syringe for precision.

- To determine the amount needed from each sample, take the total amount of serum needed by the lab and divide by the total number of samples in the pool.

Example: The lab needs 2.5 ml or 2500 microliters of serum. There are 8 animals in the pool.

2500/8 = 310 microliters (0.31 ml) of each sample to be combined

Picture 2 - Calculating the amount needed from each individual sample in pool.

Paper math

Picture 3- Pipetting the precise amount of individual sample from the collection tube into the new pooled test tube.

Pipetting serum Transfering serum to new tube

Picture 4 - Finished pooled sample. An equal amount of each individual sample has been pooled together for a combined total of the amount needed by the lab.

Finished serum sample

- Pooled samples should be adequately mixed then directly submitted to the laboratory or frozen and shipped. Allowing pooled samples to remain at room temperature for a period of time (>1 hr) potentially will result in gel formation that will adversely affect laboratory analysis.

Shipping Samples:

Once the serum or plasma has been harvested from the original sample, it should be frozen and shipped to the laboratory. Alternatively harvested samples can remain refrigerated and shipped on ice to the laboratory. Most laboratories recommend overnight shipping to minimize any sample deterioration. Contact the laboratory before shipping samples as many laboratories may have specific days of the week that samples can be received for metabolic profiling.

Picture 5 - Blood samples packed in an insulated shipping box with icepacks. The samples are in a cardboard blood-box, inside of a plastic bag.

Testing Laboratories:

Your samples should be submitted to an appropriate laboratory such as:

Sample Processing

Sample Handling and Processing

Oregon State University College of Veterinary Medicine

Michigan State University

Cornell Unviersity College of Veterinary Medicine

Texas A & M University

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