Tips, Tricks, and Frequently Asked Questions

Tips, Tricks, and Frequently Asked Questions


  • What forms of payment are accepted?
  • Per University regulations, we are only able to accept payment via check or wire transfer.  We DO NOT accept credit card.
  • Can I send a check with my sample?
  • No!  Checks can easily get lost with other paperwork in our lab.  Please wait to be invoiced.
  • Will you bill the owner?
  • Yes, provided that their complete mailing address is included on the form and the box for “bill to owner” is checked.

Sample Preparation:

  • Can I send an EDTA tube?
  • You can and we will run it; however, the reference ranges we have established were done using lithium-heparin tubes.  We do not expect there to be much of a difference, but we do not currently have data that verifies this.
  • What size tubes and how much sample do you need?
  • We will accept any size lithium-heparin tube, please be aware, DO NOT overfill the small (micro) tubes.  Tubes that are overfilled will clot easily and affect our ability to process the sample.  If sending small tubes, we recommend sending several in case one breaks in transit.  The minimum amount of total sample needed is 0.5 ml for any fluid sample (plasma, urine, whole blood).  Ideally, 1-2 mls if possible.
  • Can I use a lithium-heparin separator tube?
  • No!  Please do not use a separator tube!  Even if you do not spin the tube down, the gel/liquid that allows the separation of the red cells and plasma will interfere with processing the sample.  This can negatively impact the results.
  • Can I use an expired tube?
  • No.  Please use one that is not expired.
  • How long can samples stay in the fridge/freezer?
  • For taurine samples in the refrigerator the maximum we recommend is 1 week.  For taurine samples in the freezer the maximum we recommend 2 months.
  • Do I need to submit a fasted sample?
  • No, the sample does not need to be from a fasted animal.
  • The plasma was very hemolyzed after we spun down the sample, can I still send it?
  • No, we do not recommend sending in a hemolyzed plasma sample.  Hemolysis can falsely elevate the level of taurine detected in plasma since taurine is more concentrated in red blood cells.  The most accurate plasma sample is one that is straw-colored.  We will still run hemolyzed samples, but if we receive a severely hemolyzed sample we will contact you and request a clean sample be sent.
  • Do you only run samples for cats and dogs?
  • No, we will run samples in other species as well.  But please be aware that in many cases we will not have reference ranges available.  If you want to run samples on animals other than dogs, cats, or horses, please contact the lab to discuss your submission.
  • Do you run CAA on whole blood?
  • We do not recommend this as we do not have reference ranges for all amino acids in whole blood.  Please send either plasma or urine as we have reference ranges in plasma and are working on reference ranges in urine.  If you want to run a complete amino acid analysis on a urine sample please contact the lab first to discuss your submission.
  • Do you run urine nitroprusside tests?
  • No.
  • Will you evaluate cysteine concentrations in urine?
  • We can evaluate the concentration of cysteine in urine as part of our complete amino acid panel.  We do not have the capacity to ONLY evaluate cysteine, if you wish to have us determine the cysteine concentration in urine, you must submit the sample for a full amino acid panel.
  • Should I send plasma or whole blood for taurine analysis?
  • Although blood taurine concentration is only a fraction of the concentration in the tissues, blood and plasma taurine concentrations do change in proportion with tissue concentrations in cats.a  Whole blood taurine concentrations may be used to substantiate a diagnosis of taurine deficiency when plasma concentrations are equivocal. In addition, whole blood taurine concentrations are only slightly altered after eating, whereas plasma taurine concentration may change substantially in taurine-depleted animals.b, c  A substantial increase in plasma or serum taurine concentration can occur secondary to taurine leakage from granulocytes and platelets, as occurs with clotting or hemolysis, but analysis of whole blood taurine concentration is not confounded by these effects.

    In cases of taurine depletion in cats, plasma concentrations decline into the critical range before whole blood concentrations reach the critical range.  However, in some cases where results are equivocal, or may be suspect due to sample hemolysis, measuring whole blood in addition to plasma or instead of plasma may yield a more reliable result.

    A. Our recommendation is to prepare and submit both plasma and whole blood; simultaneously as this helps in cases where results are equivocal.

    B. Pacioretty L, Hickman MA, Morris JG, Rogers QR. Kinetics of taurine depletion and repletion in plasma, serum, whole blood and skeletal muscle in cats. Amino Acids 2001;21:417–427.

    C. Pion PD, Lewis J, Greene K, Rogers QR, Morris JG, Kittleson MD. Effect of meal-feeding and food deprivation on plasma and whole blood taurine concentrations in cats. J Nutr 1991;121:S177–S178.

    D. Delaney SJ, Kass PH, Rogers QR, Fascetti AJ. Plasma and whole blood taurine in normal dogs varying size fed commercially prepared food.  J Anim Physiol Anim Nutr:  2003;87:236-244.
  • Do you analyze serum for taurine analysis?
  • We can analyze amino acids in serum; however, we do not recommend it as we do not have normal reference ranges for serum samples.  Serum taurine concentrations are of questionable clinical value because of the variations in clotting times and methods of serum separation. In our experience, the variability in serum taurine concentrations is greater than the variability in plasma taurine concentrations (Zicker SC, Rogers QR.  Use of plasma amino acid concentrations in the diagnosis of nutritional and metabolic diseases in veterinary medicine.  Proceedings IV Congress of the International Society for Animal Clinical Biochemistry 1990:1-15).


  • What shipping carrier can I use?
  • Whichever carrier you prefer.  Be aware that USPS delivers to a central receiving facility on the university campus, so there is a delay before we get packages from them.  FedEx and UPS deliver directly to our building.
  • How do I prepare samples for shipment?
  • Please send them on ice.  If you are shipping samples the same day they are drawn, please keep them in the refrigerator until you send them.  If holding samples for 24 hours or longer before shipping, please freeze them before sending.
  • Why doesn’t the post office show your address?
  • Because the post office delivers to a central receiving facility on the university campus, our address does not always come up in their automated system.  Please hand-fill out the address label and the package should get to us.
  • Why does it take so long for you to get samples from the post office?
  • The central receiving facility on campus only delivers to our building Mondays, Wednesdays, and Fridays.  The receiving facility knows to keep packages for us in the freezer, so rest assured your samples will still be accurate.
  • What are your hours and when can I ship samples?
  • We are open Monday-Friday from 8 am - 5 pm (PST).

    The exceptions being holidays taken by the University (Martin Luther King Jr. Day, President’s Day, Cesar Chavez Day, Memorial Day, Independence Day, Labor Day, Veteran’s Day, Thanksgiving Holiday (Thurs and Fri), Christmas Eve, Christmas Day, New Year’s Eve, and New Year’s Day).

    If you plan on sending sample close to one of the University holidays, please check our website to determine if we will be able to receive your sample.  If shipping through the Post Office, only ship Monday-Wednesday.  If using FedEx or UPS you can ship Monday-Thursday.
  • You request that we ship overnight, but when does it need to arrive?
  • As long as we get the sample the following day, you can have the package set to arrive either in the morning or afternoon.
  • We drew our sample on a Friday and now can’t ship it to you until Monday, what do we do?
  • The sample will be fine if held in the freezer over the weekend until you send it to us.  If you ever have a delay in sending out a sample that lasts longer than 24 hours, please ALWAYS freeze the sample.
  • Do you provide discount shipping labels?
  • No, we do not provide discount shipping labels at this time.


  • Why does it take so long to get results back?
  • Our turn-around time for taurine is 10 business days and complete amino acid analysis is 14 business days due to the fact that we run quality controls with every group of samples we run.  This ensures the results you get back from us are as accurate as possible.  We try and get results out as quickly as possible, but please do not be concerned until the deadline for your sample approaches.  Your patience is greatly appreciated.
  • Can I as the owner receive the results?
  • Yes, but please include a note on the submission form that we need to send them to you.  Also, please include your vet’s email on the form as we need to send the results to them as well.
  • Do you have a reference range for Goldens?
  • No, our lab does not have a specific reference range for Golden Retrievers at this time.  Please refer to Dr. Stern’s handout regarding his work specifically with Golden Retrievers.
  • Is high taurine a problem?
  • There have been no reported risks associated with high blood taurine concentrations.

For Researchers:

  • Why do I need to deproteinize my sample to get an accurate measure of cysteine?
  • The amino acid cysteine forms disulfide bonds with itself and with other sulfhydryl compounds in their free form and with sulfhydryl in protein. Protein-bound cysteine is lost when plasma proteins are removed before amino acid analysis.  You will need to remove plasma proteins within 1 hour after blood collection for reliable assay of free plasma cysteine. Please see the Torres et al. (2003) article on this web site for additional information.