Diagnostic Testing

Diagnostics Available:


     This machine analyses the clotting time of blood. Rodenticides, eg.Warfarin, and some liver diseases affect the ability of the blood to clot. We will run an additional blood test using this machine to determine blood clotting time when we 
encounter a patient:  

        - with low platelet count on the standard Complete Blood Count (CBC);
        - exhibits excessive bleeding;
        - liver disease is suspected;
        - pets having consumed or suspected of having consumed a rodenticide.
 
    Often the need to determine clotting time, particularly in cases of poisonings and trauma, is crucial. Having this machine in-house will allow the clinic to determine clotting time within minutes and appropriate treatment can then be administered.   
 

     The Complete Blood Count (CBC) tells the veterinarian about the blood itself. It can tell him/her if the animal is anemic, dehydrated, or has an infection, etc. In addition to the CBC, the veterinarian often requests a chemical analysis of the blood. The chemical composition of blood provides an assessment of organ function. By reviewing different chemical components of a patient's blood, the veterinarian can assess the health and function of the animal's kidneys, liver, pancreas, gastrointestinal tract, and heart. Some of the chemicals measured in the blood are albumin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), bilirubin, creatinine, glucose, lipase, amylase, protein, urea, phosphorus, and calcium. Once the machine has analyzed the blood, the veterinarian gets a written report. The report indicates the level of each chemical from that blood sample and the level is compared to normal values. The result from the individual sample may be in the normal range, be higher than the normal range, or lower. If a value is out of the "normal" range, it may indicate that something is going on with that particular organ. This information, combined with the physical examination, symptoms presented, current history, and other diagnostic tests, aids the veterinarian in determining the diagnosis and treatment. In some cases, interpretation of the blood work can be easy. In more difficult cases, the blood work may have to be repeated at a later date or additional tests may be required to complete the diagnosis.
     The veterinarian will always request blood work on a animal that is not well because it tells him/her information that is not available from a physical examination. A disease process may be developing but not advanced far enough that outward symptoms are presented. A blood sample allows the veterinarian to examine the inner health of your pet and possibly detect disease in its early stages. This is particularly important if your animal is scheduled for surgery or is a senior pet. When 
detected early, modifications can be made to the anesthetic regime to protect your pet. Early detection of disease in seniors means actions can be taken to manage the disease and allow your pet to be healthier and happier longer.
     It must be noted that there are no standard chemical blood tests at present that detect tumors. Tumors are invasive and only when they are large enough to compromise the function of an organ do we see any irregularity in the blood work. By this time the tumor is often beyond treatment.

References:
Hendrix, C. H.,  Laboratory Procedures for Veterinary Technicians. 4th Ed.,  Mosby Inc.;  2002
Lab Work: Types of Tests. Pet Veterinarian;  Sept/Oct 1989


Complete Blood Count (CBC) 
 
      A complete blood count, or CBC, is part of the blood profile that the doctor will ask for if your pet is sick. The machine pictured analyzes different components of a blood sample.  Also, a small drop of blood from the sample is put on a slide and it is spread out to form a very thin film. The slide is then put under a microscope and the blood is analysed. The number of different types of cells in the blood are noted and counted by various methods. Neutrophils, lymphocytes,
monocytes, eosinophils, a
nd basophils make up the leukocytes or white blood cell (WBC) portion of blood. These cells play an important role in the body's defense system. An increase or decrease in the concentration of any of these components can be very informative to your veterinarian in the diagnosis of disease in your pet.  The red blood cells (RBC), or erythrocytes, main function is to transport and protect hemoglobin, the oxygen carrying pigment in the blood. In a healthy animal, the daily production of new red blood cells and daily loss of aged red blood cells should be equal. However, if there is a decrease in the production, or an increase in the destruction or loss of red blood cells, anemia results. 
   The CBC is a valuable tool for your veterinarian in diagnosing the health of your pet. 


References: Hendrix, Charles M., Laboratory Procedures for Veterinary Technicians 4th Edition, Mosby, Missouri, 2002

     One of the many procedures in our laboratory is bacteria culture and sensitivity testing. When an animal is presented with a lesion, infection, or inflammation (eg. skin or ear), the veterinarian may ask permission to run a bacteria culture and sensitivity test.
    The purpose of a culture and sensitivity test is to determine if and which bacteria are involved in the condition. The test will determine the best antibiotic to use to combat that bacteria. This culture method will isolate aerobic bacteria (air loving) which accounts for 80 to 90 percent of cultures in a veterinary practice. (1)  
    We aim to prevent the over use of antibiotics and the development of antibiotic-resistant pathogens.  To run a culture and sensitivity test, the veterinarian or
veterinary technician will take a sample of the lesion or inflamed area using a sterile swab. The sample will then be applied to a culture plate and incubated for 24 hours. A culture plate is a petri-dish covered with a special medium (eg. agar) that will support bacterial growth. If there are bacteria present, the culture plate will show growth within a 24-hour period. 
If there is no growth, there is no bacterial infection and antibiotics are not needed. Cause for the inflammation would have to be further investigated by other means. 
    If there is growth, a routine susceptibility test is run to determine the degree of susceptibility of the bacteria to several antimicrobials. Sensi-discs are applied to the plate where the bacteria has been placed. Each sensi-disc is a paper disc impregnated with a small amount of an antibiotic. The culture plate is incubated for another 24-hour period. If the bacteria are sensitive to any of area void of pathogens is called the inhibition zone. The diameter of each inhibition zone is measured and the results compared to the zone sizes on a FDA (Federal Department of Agriculture, U.S.A.) Standard Disc Method chart. The chart indicates to the veterinarian, which antibiotics the bacteria are susceptible to and those which the bacteria are resistant. Therefore, the veterinarian has a test and a tool that aids in determining which antibiotic to prescribe to best combat the infection. 
     There is a cost to having a culture and sensitivity test run. However, if an antibiotic is prescribed without a culture and sensitivity test and if the antibiotic does
not work, then a second antibiotic is prescribed usually resulting in a second visit to the clinic. There is still no guarantee the second antibiotic will be effective against the pathogen(s). By conducting the culture and sensitivity test, it ensures that:
  • an antibiotic is necessary to treat the inflammation;
  • the antibiotic prescribed is the best treatment for the infection presented and your pet’s health will soon be restored; and
  • the possibility of the bacteria developing a resistance to an antibiotic is decreased.
References:
(1) McCurnin, Bassert Clinical Textbook for Veterinary Technicians, 5th Ed., Saunders, Philadelphia, 2002. Hendrix, Page 105 
Charles M. Laboratory Procedures for Veterinary Technicians, Mosby Inc., 2002.






Radiographic Imaging (Xrays)
     Radiographs, or more commonly referred to as "x-rays", are non-luminous electromagnetic waves much like visible light, and radio and television signals. However, the wave length of x-rays is much shorter. The shorter the wave length, the greater the energy. The more energy, the greater the penetration. This is why  x-rays are capable of penetrating opaque or solid substances and tissues. As they pass through, they are captured on a photographic plate and fluoresce on the screens. This gives us an image of the internal structures of the body. Bones are very dense and x-ray is an ideal diagnostic tool to exam their structures. Soft tissue is not very dense, therefore is more difficult to interpret on the x-ray. When examining soft tissue, the veterinarian may use a contrast medium to increase the density of the structures he is examining and to increase the likelihood of correct image interpretation. At the left of the screen, you will view an x-ray of a middle aged dog that was hit by a car. The impact of the car, caused the head of the femur to be forced out of the hip socket. (See joint on the right side of the photograph. Note the femoral head on the left side of the photograph is normal.)
     When radiographs are required, the veterinarian will take a minimum of two views at 90 degree angles of each other. This gives the veterinarian a two dimensional picture of the internal structure of your pet. A two dimensional view of the internal structure of your pet allows for a more accurate interpretation and decreases the error of misinterpretation. Two views are usually required for skeletal problems. If the x-rays are for any internal soft tissue concerns, more views at timed intervals will be required and a contrast medium will be needed.
      Animals are seldom comfortable on their backs having their legs stretched out. Therefore, it is necessary to sedate the animal for x-rays. Sedation allows the staff to position the animal properly so that clear pictures can be obtained. Sedation also decreases the possibility of injury to the staff or animal if the animal is fractious or uncooperative. The level of sedation required will depend upon the difficulty of the x-rays required and the temperament and condition of the animal. If an animal is in pain and some manipulation is required to position the animal, then a deeper sedation will be required to prevent the animal struggling or suffering.
      Once again, x-rays are a form of radiation and can be harmful to people and pets. Although your pet may be anxious and you want to stay with him, this cannot be allowed. X-ray procedures are regulated by the Occupational Health and Safety Act. Only authorized clinic personnel are allowed to be present during the procedure. All safety precautions and equipment are used to protect the pet and the clinic staff.
    When the doctor recommends x-rays, cost often becomes a major factor to the client. However, to determine a proper diagnosis, a minimum of two views and sedation is required. In all cases, it is in the best interest of our pet's welfare, that this procedure is being recommended.

References:
McCurnin, Bassert Clinical Textbook for Veterinary Technicians, 5th Ed., Saunders, Philadelphia, 2002


Trypsin Test
     Occasionally an animal will come into the clinic and seems to be doing well but has poor body condition and sometimes mild but chronic diarrhea. In spite of a ravenous appetite and increased food intake, it just does not seem to put on weight or continues to lose weight. When the biochemistry and CBC (complete blood c
ount) are normal, the veterinarian may ask for a trypsin test.
     Trypsin is an enzyme produced in the pancreas that assists in the digestion of food. It breaks down the proteins so that they can be absorbed by the intestines. If an animal lacks this enzyme, it cannot extract all the nutrients from its food and therefore does poorly.
     The trypsin test is a simple test that can be run in the clinic. The test requires a warm fecal sample. A small amount of the feces is dissolved in carbon bicarbonate. A piece of undeveloped x-ray film is put in with the sample and this is incubated for thirty minutes. If trypsin is present, the gel coating on the film will be removed from the film. If the gel is not removed, trypsin is not being produced by the pancreas. Fortunately for the animal, the veterinarian will prescribe a medication in the form of a food supplement to replace the trypsin that is not being produced and the pet should be able to live a normal life.

References:
Hendrix, C., Laboratory Procedures for Veterianry Technicians. 4th Ed., Mosby Inc, Missouri, 2002 
Birchard, Sherding, Saunders Manual of Small Animal Practice, W. B. Saunders Company, Pennsylvania, 1994 

     Urinalysis is a relatively non-invasive laboratory procedure that provides a wealth of information about the urinary tract, the kidneys, and liver, and can detect diabetes and dehydration. There are several components to a complete urinalysis. Click on "Urinalysis Information Sheet" to review the details of this in-house service we provide.



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Arlene Wright,
Sep 5, 2014, 6:04 AM
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