Explanation of Diagnostic Tests used in Reptiles
Robin Scott, DVM
Safari Animal Care Centers
2450 E Main Suite D, League City, Texas
Turtles and Tortoises come packaged in a hard bony shell divided into the carapace (rounded top shell) and the plastron (flat bottom shell). This shell provides support and protection to the internal organs but is a barrier to the type of complete physical examination veterinarians are accustomed to performing in our soft-bodied pets such as dogs and cats. The importance of a physical examination cannot be ignored however there are limitations. Body weight is very important and should be monitored at home using a grams scale in smaller pets (under 2000 grams) and a platform type scale in pets greater than 2000 grams. It is important that you weigh your pets regularly so that you know what is normal for your pet. Any steady or sudden loss in weight can be an indication of illness and should signal the need for a visit to your veterinarian.
Your veterinarian should systematically examine your pet as follows:
Laboratory tests and other diagnostic procedures give us a window into the body that cannot be determined just by physical examination. Diagnostic tests vary in their level of invasiveness and cost. Much can be ascertained through the use of diagnostics tests some of which will be discussed below.
Blood work: In general basic blood work consists of a combination of the Complete Blood Cell Count (CBC) and the serum biochemistry profile. A small blood sample is collected from one of several sites i.e. the jugular vein in the neck, the brachial vein on the back of the front leg, the dorsal tail vein on the top of the tail and the supravertebral vein near the spine. This sample is processed by a lab for the following:
CBC measures the number of red blood cells, which are important carriers of oxygen to the tissues. A decrease in the red blood cell count is an indication of anemia. These pets may have weakness, pale gums and inactivity. Causes are many but include chronic diseases and malnutrition, parasites, kidney disease and blood loss.
The White Blood Cell count (WBC) evaluates the numbers of several different types of cells that respond to infection or inflammation. The most common cells evaluated are the heterophils, which are increased in infection and inflammation; these are usually the first cells to respond. The monocytes are cells that respond later in disease and reflect a more chronic or long standing condition.
The Serum Biochemistry profile evaluates the levels of different enzymes and chemicals in the blood. The most common ones to look at are:
Protein which gives an indication of the overall body condition, too low may indicate disease causing loss of protein such as parasites or disease of the digestive tract causing protein to the lost into the intestine or failure to absorb protein from the intestine; whereas too high may indicate dehydration or increased response of proteins called globulins to disease.
Calcium levels are decreased in malnutrition, metabolic bone disease and chronic egg laying. Calcium is normally increased in egg laying females and can be used to determine seasonal conditions such as reproductive activity.
Phosphorous is evaluated in combination with calcium. Phosphorus can be elevated normally in egg laying females indicating increased utilization from the bone (i.e. calcium is pulled from the bone and phosphorus follows with it). The normal ratio of calcium to phosphorus is 2:1 i.e. the calcium level should be at least 1.5-2 times that of the phosphorus level. Phosphorus will often be increased in pets fed diets with excessive phosphorus or calcium deficient diets. Increased phosphorus is often the first indication of underlying renal (kidney) disease.
Uric acid is a waste product from the metabolism of protein. It is removed from the body by the kidneys. Uric acid can be increased in pets that are dehydrated and in pets in severe stages of kidney disease.
CPK is a muscle enzyme that is increased in conditions of starvation, and muscle trauma. This enzyme can be increased just from the handling of a struggling tortoise or from a difficult blood collection.
Radiographs are non invasive and allow for a view of the bony structures and internal organs. The organs are seen in outline and can be evaluated for size and shape, presence of abnormal gas patterns in intestine and lungs, foreign material in the gut, abnormal areas of calcium deposits in organs, presence of eggs and stones in the bladder, while the skeleton can be evaluated for bone density, fractures and previous injuries and swellings of the joints. Radiographs are particularly important if pneumonia is suspected.
Ultrasound can be used for limited evaluation of the liver, kidney and reproductive tract. This requires specialized equipment and training.
Coelomoscopy uses a rigid scope placed into the coelomic cavity to visualize the abdominal organs. This can be used to obtain tissue samples for culture for bacterial organisms and for microscopic evaluation of the tissues for disease (histopathology and cytology). This requires sedation and is a surgical procedure.
Bacterial culture and sensitivity testing involves the sampling of discharges, exudates from wounds, urine or feces for the presence of abnormal bacteria and fungi. These samples are collected and placed onto a growth media that allows the organisms (if present) to grow. They are then isolated, identified and tested against a group of antibiotics to determine which antibiotic is best for treatment. This is important since bacterial infections are common in our pets and treatment of bacterial infections in reptiles may require several weeks to months of antibiotic therapy. It is important to know if you are using the most effective antibiotic.
Urine can be analyzed for the presence of blood, which is an indication of infection of bladder and/or kidneys and may indicate presence of a bladder stone.
Fecal material should be evaluated for the presence of parasite ova (eggs) and protozoal parasites that are often present and can cause severe disease, especially in young reptiles. Fecal analysis involves the microscopic evaluation of a direct smear of the fresh feces for live protozoa and evaluation of a flotation (chemically prepared sample that allows for concentration of eggs when present) for the presence of eggs. It is a good idea to worm your pet periodically to eliminate parasites even in cases when fecal tests are negative as the eggs are often shed in low numbers or intermittently and may be missed.
Copyright (c) 2004 Gulf Coast Turtle and Tortoise Society
Permission is granted to copy for non-profit use with proper credit given. For any other use you must obtain permission.
Gulf Coast Turtle and Tortoise Society
1227 Whitestone Lane
Houston, TX 77073
Email us for quickest response: