Miscellaneous Chemistry Tests

Creatine Kinase

An enzyme that is found predominantly in cells of the heart, brain, and skeletal muscle; released when cells are damaged

CK

An enzyme frequently assayed if an animal has an increased AST level with no clinical signs of liver disease

Creatine Kinase

An enzyme that is found predominantly in cells of the heart, brain, and skeletal muscle; released when cells are damaged

CK

An enzyme frequently assayed if an animal has an increased AST level with no clinical signs of liver disease

CK

An enzyme that can be evaluated in CSF as an ancillary diagnostic test for non-specific damage to neural tissue; useful guide for prognosis in K9 neurologic cases and premature foals; increases may be seen after seizures

Liver Injury

Suspected when increased ALT is greater than increased AST without an increase in CK

Skeletal Muscle Injury

Suspected when increased ALT is greater than increased AST with an increase in CK

CK-BB

Brain type isoenzyme of creatine kinase

CK-MB

Cardiac type isoenzyme of creatine kinase

CK-MM

Skeletal muscle type isoenzyme of creatine kinase

Isoenzymes of CK

Can be isolated to identify the source of increased creatine kinase levels

Increased CK

Caused by IM injections, vigorous exercise, persistent recumbency, electric shock, surgery, laceration, bruising, hypothermia, myositis, and other myopathies

Oxidizing Agents

Can cause falsely elevated CK levels in blood samples

Cardiac Troponin

A protein involved in regulating the initiation of skeletal muscle contractions; can be used to evaluate cardiac muscle damage

CTn

The degree of increase in this protein aids in determining the severity of cardiac muscle damage and the elapsed time since the damage occurred

Brain Natriuretic Peptide

A hormone secreted by myocytes that function in the maintenance of blood pressure; increased levels occur with increased ventricular filling pressure

BNP

Aids in the diagnosis of heart failure

Lactate

The anionic form of lactic acid; produced by anaerobic cellular metabolism and presence does not indicate any specific disease

Lactate

Presence of this compound in increased levels indicates hypoxia or hypoperfusion

Lactate Dehydrogenase

A serum enzyme that catalyzes the conversion of lactate into pyruvate; has many isoenzymes with different amounts present in different tissues

Liver, Muscle, and RBCs

Major sources for increase blood lactate dehydrogenase levels

Adrenocorticotropic Hormone

A hormone that stimulates adrenocortical growth and secretion, particularly of glucocorticoid-synthesizing tissue

Cortisol

A steroid hormone produced by adrenal glands

Hyperadrenocorticism

The abnormally increased secretion of adrenocortical hormones (cortisol); aka Cushing’s disease

Hypoadrenocorticism

A deficiency in the production of mineralocorticoid or glucocorticoid steroid hormones; aka Addison’s disease

Hyperadrenocorticism

Caused by brain / pituitary tumors, idiopathic adrenal hyperplasia, or neoplasia of one or both adrenals

Glucocorticoid Therapy

The most common cause of hyperadrenocorticism and is often accompanied by paradoxically atrophied adrenal glands

ACTH and Cortisol Concentrations

Values that aid in differentiating primary from secondary hypoadrenocorticism

ACTH Stimulation Test

A test used in those with suspected Addison’s or Cushing’s disease. Also indicated to differentiate between iatrogenic and spontaneous Cushing’s disease

ACTH Stimulation Test

A test that evaluates the degree of adrenal gland response to administration of exogenous adrenocorticotropic hormone; the degree of response reflects the adrenal glands’ size and development

Hyperplastic Adrenal Glands

Lead to an exaggerated response to an ACTH stimulation test

Hypoplastic Adrenal Glands

Lead to a diminished response to an ACTH stimulation test

ACTH Stimulation Test

A non-specific screening test for adrenal gland dysfunction; > 80% accurate for hyperfunction in dogs and > 50% in cats

Dexamethasone Suppression Test

An endocrine system test designed to detect hyperadrenocorticism; evaluates adrenal glands differently than ACTH stimulation test by using adrenal feedback loops

Low-Dose

Type of dexamethasone suppression test that confirms or replaces the ACTH stimulation test for Cushing’s disease

High-Dose

Type of dexamethasone suppression test that is used to differentiate between pituitary causes of Cushing’s disease from adrenal causes; suppression only by this test indicates pituitary origin

Dexamethasone

A compound that suppresses ACTH release from a normal pituitary gland leading to a drop in plasma cortisol concentration

Abnormal Adrenal Glands

Will continue to secrete cortisol in the face of a high-dose dexamethasone suppression test