A 'biopsy' is a medical procedure that involves cutting a tissue sample from a diseased area of an animal in order to run a series of tests on it in a controlled laboratory environment. This will allow the vet to better identify the problem and decide on an accurately-targeted course of treatment. A gastrointestinal biopsy would involve tissue from the digestive system in order to diagnose a gastrointestinal disease or disorder in a cat.

It should be noted that a biopsy is not a treatment in itself, and should not be confused with an excision, which would involve cutting a whole area of diseased tissue out of the body in order to fix the problem. Instead, biopsies should be thought of as a diagnostic tool, letting the vet better understand their patient's condition.

Prior to performing the procedure, the vet will want to determine exactly which kind of biopsy they want to carry out. Tissue samples can be obtained either via an endoscope (which is minimally invasive and consists of threading a camera down the cat's throat to retrieve the sample), via a needle (which can be guided to the targeted tissue using ultrasound), or via surgery (which will involve cutting directly into the intestine or stomach). In all cases, the cat will be subdued with a dose of general anesthetic and if surgery is being performed, its belly will be shaved and cleaned. The endoscopy can be done in the space of a few minutes, as the vet simply has to thread the endoscope down the animal's throat and cut a small tissue sample from the digestive tract and extract the tube. The needle will require a little more finesse to locate the area in conjunction with ultrasound, but the process should only take under ten minutes altogether. A surgical biopsy, however, is rather more complicated. Firstly, the vet has to make a lengthwise incision along the belly of the cat in much the same manner as when performing a laparotomy, before uncovering the target area of the stomach or intestines. Next, they must carefully cut out a segment of the organ and remove it from the body before suturing the wounds shut and applying disinfectant.

In general terms, the biopsy is an extremely useful diagnostic tool that allows vets to quickly perform a series of tests that may shed light on an otherwise unknowable condition. This is especially true when dealing with growths, as whilst the majority may end up being benign, catching a dangerous cancer in its early stages can provide a massive advantage when moving forward with treatment. Furthermore, a surgical biopsy can provide the vet with an opening to remove the entire growth from the cat's body if the opportunity presents itself. Some people may wish to eschew biopsies in favor of techniques such as imaging scans, but they should keep in mind that they tend to be much less effective at diagnosing the issue.

Following the procedure, the cat will need time to rest and recuperate, with its activity being restricted for a few days so as to conserve its energy. Furthermore, their diet will have to be kept simple and bland so as to not irritate the stomach and slow down the healing process. Cats recovering from a surgical biopsy will require extra care and attention, needing regular doses of painkillers for the three weeks or more until the wound heals and a course of antibiotics to prevent infection. It should be noted that the vet will most likely want to schedule follow-up appointments to act upon the results of the biopsy, so particular care should be taken when transporting the cat to ensure its surgical wound remains intact. 

The price of a gastrointestinal biopsy for a cat can vary quite widely. The cost will depend on factors such as the age of the cat and the type of biopsy being performed. Biopsies being performed via a needle or endoscopy can be expected to be priced at roughly $400 to $500, with surgical biopsies commanding a much higher price of around $800 due to the skills needed to perform the operation. Other methods of analyzing the interior of the gut tend to cost roughly the same (with MRI scans being around $600), yet sacrifice much of the detail that can be gained from a direct tissue sample.

Although it is a very effective technique, a gastrointestinal biopsy is not without risk and owners should be aware of these issues if they choose to go ahead with the procedure. As it directly cuts into the interior of the digestive tract, there is a small chance that a biopsy wound can become infected, possibly developing into an ulcer or causing damage to the stomach and intestines. Usually, this risk is mitigated via the use of antibiotics, though it remains a small possibility. Additionally, some tumors can, once physically breached, disgorge numerous cancerous cells that then spread throughout the body and cause the appearance of tumors elsewhere. That said, this is a relatively rare occurrence and will usually only take place if the tumor was malignant.

To avoid damage to or infection of the gastrointestinal tract, owners should try to maintain a tidy living environment for their pet, as this will prevent them from swallowing objects that may go on to damage their gut. Cancers meanwhile, are somewhat hard to predict, with many being due to hereditary genetic defects that are hard to screen for. However, by feeding the cat a well-balanced diet and providing it with a healthy level of exercise, owners can go a long way towards eliminating conditions caused by environmental factors or stressors.