Touchstone Diabetes Center

Metabolic Phenotyping Core

Frequently Asked Questions

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How much sample do I need to provide?

This depends entirely on what tests you want to run. For anything on the Vitros 250, it is 40uL plus 10uL per test. e.g. If you wanted to run cholesterol and triglyceride, you would need to provide 60uL of sample.

Unfortunately, for the ELISA kits the sample volume ranges from 10-100uL, depending on the protocol.  

Most of the cytokine panels use 60uL of sample to run 1-20 cytokines. A more precise number will be given when you inform the Core of the cytokines you would like to run and on what species.

How do I pay?

At the end of each month, an invoice is sent out to each PI for the services rendered that month. He/She then pays with an IDR. For outside investigators a PO number will be required

in advance.

Do you do tests on urine?

Yes, we can do the following tests on urine: AMYL, BUN, Ca, CREA, GLU, K , Mg, Na , PHOS, URIC, and UPRO. They are done on the Vitros 250, so sample volume and price can be found on the Vitros link to the left.

What is the best sample collection method?

Any method to decrease the amount of hemolysis is best. For blood draws, collect blood using at least 21-gauge needle to avoid hemolysis. Serum can be obtained by allowing the blood to clot at room temperature for 30 minutes and then centrifuging at 2000-3000 rpm for 10 minutes at 4°C. Serum separator tubes that can be purchased from Becton Dickinson (order number 365956, vendor: J J Nita Burgoon Co.).

What kind of sample prep do I need to do?

All of the tests on Vitros 250 need no sample prep.  However, the least amount of hemolysis possible is best.  Only for a few analytes do specific inhibitors need to be added. A couple of the more common ones are DPPIV for GLP-1 measurements, Protease Inhinitor cocktail for amylin, and Serine protease inhibitor for active ghrelin. Leptin, insulin, and free fatty acids are common ones that do NOT need sample prep. If you are unsure about an analyte in question, please contact Sarita Shah.

How far in advance do I need to contact the Core about samples/mice?

Please allow a minimum of two weeks for ELISA and Luminex plates to be ordered and come in. For Vitros, samples can be brought in at any time to the Metabolic Core main lab. An email to the core is strongly recommended, especially for unstable metabolites. Reservations for the metabolic cages are first come first serve, so it is best to reserve them as early as possible.  

What is the turn-around time?

Depends on the type of assay and the length of the queue .Contact the corresponding core members for accurate turn around times (times may vary from 2 days up to 5 weeks).

How do I need to bring the samples?

For sample collection and storage instructions please contact the corresponding core member.

What is the sample submission protocol for LC-MS/MS sphingolipid quantitation?

General guidelines for all sample types.

Consistency in sample handling and collection is critical. For samples belonging to the same study, please avoid changes in the sample collection technique, time of sampling, time from collection to freezer, etc.

Samples should be frozen as soon as possible after collection and stored at -80C until shipping. Flash freezing in liquid nitrogen is ideal. However, if these resources are not available, immediate placement of tubes in a -80 °C freezer is acceptable.

For plasma and serum samples, please use polypropylene cryovials (or polypropylene microcentifuge tubes for volumes of plasma and serum smaller than 100 microliters).

For tissue samples , please never allow the tissue to thaw. Bring approximately 100 mgr in microcentrifuge polypropylene tubes.

Required sample amounts:

Human plasma/serum 200 microliters
Mouse plasma/serum 50-75 microliters.
Tissue samples 100 mg.

Please label sample tubes with permanent markers while tubes are warm (cold tubes will not hold the ink) or use specialized freezer safe labels. Include as much information as possible from each sample (volume of sample, sample weight, etc.). Please exclude any patient identifier in the case of human samples.

Please label samples using a series of sequential numbers.

Samples should be shipped on dry ice including a hard copy of the list of samples contained in the shipment. 
Please email Ruth Gordillo and copy Mr. Steven Connell in advance of sending the samples. A more detailed sample collection and shipping protocol will be provided.

Ship samples to:

Steven Conell
Ruth Gordillo, Ph.D.
Touchstone Diabetes Center
Department of Internal Medicine
The University of Texas Southwestern Medical Center
5323 Harry Hines Boulevard
Dallas, TX 75390-8549


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