Plasma protein abnormalities are associated with a wide variety of disease processes and are a significant biochemical finding in both dogs and cats. The plasma proteins are comprised of albumin, globulin and fibrinogen fractions. The chapter considers methods of measuring protein, serum protein electrophoresis, functions of plasma proteins, hyperproteinaemia, hypoproteinaemia and acute phase proteins. The chapter also includes case studies.

The major electrolytes in the body are potassium, sodium, calcium and magnesium. Electrolyte concentrations are closely controlled by the action of multiple hormones and by the kidneys. Derangements affect many body organs including the nervous system and cardiac and skeletal muscle. Major imbalances can cause severe clinical signs and death. This chapter looks at measurement of electrolyte concentrations in serum and plasma, disorders of potassium homeostasis, disorders of sodium homeostasis, disorders of chloride homeostasis, disorders of magnesium homeostasis and disorders of calcium homeostasis. Case studies are included.

Free skin grafts involve the transfer of variable thicknesses of dermis, with the epidermis, from a donor site to the recipient wound site. In veterinary wound management, grafts are exclusively autografts (i.e. donor and recipient are the same patient). Free grafts find occasional application in the reconstruction of full-thickness skin defects involving the extremities of the dog and cat. However, by comparison with other reconstruction techniques has a number of limitations. Indications for skin grafting; How skin grafts ‘take’; Harvesting the graft; Preparing the graft; Recipient sites; Applying the graft; Care of the graft; Interpreting graft appearance; The functional and cosmetic result; and Troubleshooting are all covered. Case examples: Free skin grafting for a chronic open wound; and Free skin grafting for a burn wound.

Hyperthyroidism is a common condition of senior and geriatric cats that is present in 6% of cats over the age of nine years old. Similarly chronic kidney disease is common in old cats, hence it is not uncommon for cats with CKD to have concurrent hyperthyroidism, and vice versa. This chapter includes sections on hyperthyroidism and chronic kidney disease in cats; systemic effects of hyperthyroidism; systemic effects of treatment of hyperthyroidism; effect of iatrogenic hypothyroidism on renal function; predictors of the development of azotaemia following treatment of hyperthyroid cats; and management of hyperthyroid cats with concurrent, or masked, CKD. Case examples: Cat with polydipsia, diarrhoea and weight loss; Cat with weight loss and polyphagia; Cat with polydipsia, polyphagia and diarrhoea

Each adrenal gland is composed of acortex and a medulla, which are functionally separate endocrine glands. The most common disorders affect the adrenal cortex and cause eitjer hyperadrenocorticism (HAC) or hypoadrenocorticism. This chapter considers canine hyperadrenocorticism, feline hyperadrenocorticism, canine hypoadrenocorticism, feline hypoadrenocorticism and other adrenal diseases. Readers will also find case examples included.

Cerebrospinal fluid (CSF) collection and laboratory analysis are recommended as part of the investigation of central nervous system (CNS) disease. A definitive daignosis on the basis of CSF laboratory evaluation alone is rare, but the laboratory evaluation of CSF may provide documentation of normal or abnormal findings and help make distinctions among various differential diagnoses. This chapter covers CSF collection, laboratory analysis of CSF, normal and abnormal CSF and CSF findings in selected clinical conditions. Case examples are included.

The gastrointestinal (GI) tract is relatively inaccessible, and laboratory investigations are an important component of the diagnostic approach to GI diseases. Although alone they often do not provide a definitive diagnosis, they are helpful in ruling out non-GI causes of GI signs, narrowing the list of differential diagnoses and directing further more specialized and potentially more invasive diagnostic procedures. The chapter discusses a diagnostic approach to gastrointestinal problems, routine diagnostic procedures and specialized diagnostic tests. The chapter also contains case examples.

This chapter looks at laboratory evaluation of hypoglycaemia and hyperglycaemia. The following topics are considered: glucose homeostasis, measurement of blood glucose, hypoglycaemia, hyperglycaemia and diabetes mellitus. Case studies are included.

Laboratory evaluation of joint disease is based on examination of synovial fluid. Synovial fluid analysis rarely yields a definitive aetiological diagnosis but it does help to confirm the presence of an arthropathy, to discriminate between broad categories of joint disease, and to guide the choice of further tests (e.g. serology, culture, polymerase chain reaction (PCR), antinuclear antibody titre, rheumatoid factor titre, etc.). This chapter considers physiology and composition, pathogenesis of joint effusion, indications and contraindications for arthrocentesis, arthrocentesis technique, synovial fluid analysis and further tests. Case examples can be found at the end of this section.

Muscle disease can affect skeletal (striated), cardiac and, more rarely, smooth muscle. It can be primary or secondary to other systemic disorders but can be difficult to recognize clinically owing to its non-specific signs. Even when muscle disease is supected, the appropriate diagnostic work-up is often poorly understood and test results can be misinterpreted. This chapter discusses clinical sign sof muscle disorders, laboratory evaluation of muscle disorders and tests used in the investigation of skeletal (striated) muscle disorders. Case examples are included.