Electrolytes are the salts and metallic components that are dissolved within the blood serum (serum is the liquid portion of blood). The electrolytes of greatest clinical importance are sodium, potassium, chloride, bicarbonate, phosphorus, and calcium. It is important to detect changes in electrolyte concentrations so that these changes can be treated before the situation becomes severe or life-threatening.

Serum biochemistry measures the amount of enzymes, proteins, sugar, electrolytes, minerals, and hormones found in the liquid portion of the blood. Testing for these substances provides information about the body’s organs and tissues, as well as the metabolic state of the animal. This article provides general information on the most routinely measured factors in serum and common reasons for abnormal readings.

Adrenocorticotropic hormone (ACTH) is produced in the brain and regulates the production of cortisol. When blood cortisol levels are low, it is secreted to stimulate more production, and when blood cortisol levels are high (like from an adrenal tumor), ACTH production is suppressed. ACTH testing alone cannot be used to diagnose Cushing’s disease but can help determine what type of Cushing’s disease the patient has.

X-ray images are produced by directing X-rays through a part of the body towards an absorptive surface such as an X-ray film or electronic sensor. The image is produced by the differing energy absorption of various parts of the body. Bones are the most absorptive and leave a white image on the screen, whereas soft tissue absorbs varying degrees of energy depending on the density, producing shades of gray on the image. Air on an X-ray is black. X-rays are a common diagnostic tool used for many purposes.

Having your pet properly prepared for a blood test helps to ensure that the results are as accurate and reliable as possible. Preparation for these two types of tests is slightly different. Your veterinarian will give you specific instructions before your appointment. It is important that you follow these instructions exactly to ensure accurate test results.