Frequently Asked Questions

Expand all Collapse all
+ _ 1. Information on sample requirements and shipping guidelines

For our tests, we recommend an 8-12 hour fasted serum sample for non-diabetic patients, and a 6 hour fasted serum sample for diabetic patients. Please note that the serum MUST be separated from the blood clot and serum should be transferred into a new tube.

We recommend that you send your sample with Fed-Ex or UPS.

For more specific instructions on sample requirements and shipping, click here.

+ _ 2. How much serum do I need to submit?

For specific guidance on the volume, click here.

+ _ 3. How to ship from within the USA or from overseas?

Shipping From Within The USA
We strongly recommend the use of a secondary carrier service, such as FedEx or UPS for submission of samples to the Gastrointestinal Laboratory. Please do not use the US Mail service, as we have experienced excess delays with this carrier. Please note that the GI Laboratory does not accept packages shipped “Bill Receiver”. If we are paying for sample shipping in one of our studies, we will supply airway bills for sample submission. Unfortunately, we have to refuse packages arriving at the GI Lab marked “Bill Receiver”, and we are not liable for any resultant delays.

Shipping From Overseas To The USA
We strongly recommend the use of a multinational carrier, such as UPS or FedEx, for submission of samples from overseas to the Gastrointestinal Laboratory. These carriers have inhouse customs agents that can handle the importation paperwork. Samples delayed in customs may be stored in suboptimal conditions and experience considerable delays. Please attach to the outside of the box, and include a copy within the box, a signed letter on your official letterhead that states the following:

“This shipment contains only canine/feline serum, urine or fecal samples (word as appropriate) for diagnostic testing. These samples are not contagious or infectious, and have not been derived from animals exposed to agents of agricultural concern. This shipment has no commercial value.”

We cannot accept samples from exotic or agricultural species from outside the United States. This includes feline and canine exotic species. If you have specific questions, please contact us directly via email ( BEFORE shipping your samples.

+ _ 4. What test should I use?

Veterinarians often ask which tests we recommend for dogs and cats with clinical signs of gastrointestinal disease. While every patient is different, there are some guidelines we use to determine a systematic diagnostic approach.

For dogs and cats with chronic diarrhea we first recommend evaluation for parasitic infestation. Even if fecal smears and flotation are negative, the patient should still be treated with a broad-spectrum anthelmintic agent.

If diarrhea continues or in patients with chronic vomiting we recommend ruling out secondary causes of chronic diarrhea and/or vomiting by performing a complete blood count, serum chemistry profile, urinalysis, and in cats above 6 years of age a total serum T4 concentration.

If no specific abnormalities are determined a reasonable next step is to evaluate the exocrine pancreas and the small intestine. In dogs with chronic diarrhea and weight loss we recommend starting out with a serum cTLI concentration to rule out EPI and serum cobalamin and folate concentrations to rule out chronic intestinal disease, such as small intestinal bacterial overgrowth or malabsorptive disorders.

If the clinical picture includes anorexia, vomiting, or abdominal pain the initial work-up should also include measurement of serum cPLI concentration to rule out pancreatitis.

As pancreatitis in cats usually leads to rather non-specific signs we would recommend the measurement of serum fTLI, fPLI, cobalamin, and folate concentrations in all cats with chronic signs of gastrointestinal disease. We have recently found that hyperthyroid cats appear to be at increased risk for presenting with low serum cobalamin, low serum folate, or both. Thus, we recommend measurement of cobalamin and folate in all hyperthyroid cats, to screen for subclinical small intestinal disease.

+ _ 5. How can I obtain my results as fast as possible? What are my User ID and password?

If your practice does not have an email address registered with the GI Lab, please consider doing so. Our database system allows you to access results over the internet as soon as the assays are completed. Results are available via our lab webpage immediately, and a full report is emailed each day. A follow-up fax or hard copy by US mail will follow later. So please be sure to enter an e-mail address on your accession forms to ensure the earliest possible reporting of results. Your e-mail address is your username. On our result reports, your clinic ID number is given in the upper left corner of the page, directly below the email address we have recorded for your clinic. The clinic ID number is your password.

+ _ 6. Does giving glucocorticoids (prednisone or dexamethasone) to a dog/cat affect the results of the TLI/PLI?

We have no evidence that the administration of prednisone, prednisolone or dexamethasone alters the serum concentrations of TLI or PLI in a clinically significant manner in clinically healthy animals. Thus the administration of glucocorticoids is highly unlikely to lead to either increases or decreases in serum TLI or PLI concentrations that would alter your clinical diagnosis.

If the animal has a disease causing malabsorption or increased release of pancreatic enzymes, and if the disease is glucocorticoid responsive, then abnormal values may become more normal or even normal when glucocorticoids are given. This may influence your interpretation, and you should consider the possibility that a high normal or only moderately increased TLI or PLI, in an animal with clinical signs of pancreatic disease that is receiving glucocorticoid therapy, may have been higher in the absence of the glucocorticoids.The serum vitamins, cobalamin and folate, usually do not show any change with prednisolone therapy alone,even if the diarrhea or weight loss improves. Typically you have to give vitamin supplements to make things normal, as we have described on our page regarding cobalamin therapy.

If you suspect that glucocorticoid administration has altered the clinical interpretation of TLI/PLI results, it may be worthwhile to draw a new sample after withdrawing the glucocorticoid therapy, assuming that the withdrawal of glucocorticoids is not contraindicated and consistent with the ongoing care of the patient. We would suggest waiting for at least 10 days after complete withdrawal of glucocorticoids before collecting a new serum sample.

+ _ 7. Does the serum for TLI, PLI or Cobalamin/Folate assays need to be cooled or frozen during transport?

The various analytes have different stability in serum. Serum TLI and PLI are stable for up to 2 weeks at room temperature. However, serum folate shows limited stability at room temperature. Therefore, serum samples for folate analysis should be kept at 4ºC for not longer than 48 hours, but freezing is preferred. Furthermore, folate is light sensitive and samples should be stored in the dark or wrapped in foil. We recommend that samples for serum cobalamin/folate analysis are shipped overnight either frozen or at least with included ice packs to keep them cooled during shipment.

+ _ 8. Should I send samples overnight or by regular mail?

We recommend that you send your sample with Fed-Ex or UPS. Fecal samples for fecal alpha1-Proteinase Inhibitor need to arrive frozen at the laboratory. We highly recommend shipping such samples overnight on dry ice.

Serum TLI and PLI are stable for up to 2 weeks at room temperature. We recommend that samples for serum cobalamin/folate analysis are shipped overnight either frozen or at least with included ice packs to keep them cooled during shipment.

Note: Due to delivery procedures at such a large university, packages sent with the US Postal Service can often be delayed or even lost within departments. Please DO NOT use the US Postal Service as a carrier. We also offer a Fed Ex discounted shipping program through our website. Contact the lab for your username and password.

+ _ 9. Will the results be affected if samples are hemolyzed?

Hemolysis will cause an increase in serum folate concentrations (because RBC’s contain a much higher concentration of folate than serum) and a false decrease in serum bile acids concentrations (an artifact because of the methods that we use). Hemolysis will also affect C-reactive protein concentrations.

+ _ 10. Can I get some more information on cobalamin supplementation?

We often recommend supplementation of cobalamin (Vitamin B12) in animals with gastrointestinal disease. Further information on the importance of cobalamin in the treatment of gastrointestinal disease can be obtained by clicking here. If an animal is receiving cobalamin supplementation, it will dramatically elevate the serum cobalamin concentration, this should be considered when requesting the cobalamin and folate assay.

+ _ 11. What address do I use to send the sample?

Shipping address:
Gastrointestinal Laboratory
Texas A&M School of Veterinary Medicine & Biomedical Sciences
4474 TAMU | College Station, TX 77843-4474