Correlation of changes in blood chemistry with pathological changes in the animal's body: II Electrolytes, kidney function tests, serum enzymes, and liver function tests.

The numerous physiological and nutritional factors which influence the concentration of serum calcium are considered. The causes of hypercalcaemia and hypocalcaemia are briefly discussed, with particular reference to the clinical symptoms and pathology. The effect of the acid-base status on the serum-ionized calcium level is stressed. The causes of changes in the serum concentrations of phosphorus and magnesium are briefly reviewed, along with the abnormalities of lactate, pyruvate, and hydrogen ion concentrations. The kidney function tests, blood urea nitrogen, serum creatinine, and the renal clearance tests are discussed, with emphasis placed on correlating their results with the findings from repeated urinalyses. The important physiologic influences and pathological processes which result in changes in the concentrations of these parameters are delineated. The causes of increases in the serum enzymes, alkaline phosphatase, alanine transaminase, asparate transaminase, lactic dehydrogenase, sorbitol dehydrogenase, glutamic dehydrogenase, gamma glutamyl transpeptidase, creatinine phosphokinase, amylase and lipase are discussed. The changes in serum bilirubin concentration and its components are fully described, with emphasis placed on the correlation of the findings with urinalysis data and the complexities resulting from the numerous pathologic conditions causing jaundice. These conditions are listed for each of the domestic animals. The other liver function tests, bromosulphthalein dye retention or excretion, serum uric acid and blood ammonia concentration are briefly considered. All the tests described are very useful, and frequently essential, in aiding the veterinary practitioner to arrive at a diagnosis and prognosis, but they never replace clinical acumen.