GLOSSARY [CC - Tietz] Fundamentals of
CLINICAL CHEMISTRY
Absorbance (A)
✓ ~~~ The capacity of a sub- stance to absorb radiation; expressed as the logarithm
(log) of the recipro cal of the transmittance (T) of the substance.
Absorption Spectrum
✓ ~~~ The graphical plot of absorbance versus wavelength (the absorbance
spectrum) for a specific compound. Absorptivity: A measure of the absorp- tion of
radiant energy at a given wavelength and/or frequency as it passes through a
solution of a sub- stance at a concentration of 1 mol/L; expressed as the absorbance
divided by the product of the concentration of a substance and the sample path
length.
Accreditation
✓ ~~~ An audit technique that is used to assess the quality of a process by checking
that defined operational standards are being followed, in this case in the
performance of point-of-care testing.
Acid Phosphatase
✓ ~~~ An enzyme of the hydrolase class that catalyzes the cleavage of
orthophosphate from orthophosphoric monoesters under acid conditions.
Acid-Base Balance
✓ ~~~ The homeostatic maintenance of acids and bases within the body to achieve a
physiologic pH (approximately 7.40).
Acid-Base Measurement
, ✓ ~~~ The measure- ment of whole blood pH and blood gases.
Acidemia
✓ ~~~ An arterial blood pH < 7.35.
Acromegaly
✓ ~~~ A chronic disease of adults caused by hypersecretion of pituitary growth
hormone and characterized by enlargement of many parts of the skeleton.
Activation Energy
✓ ~~~ In enzymology, the energy required for a molecule to form an activated
complex. In an enzyme-catalyzed reaction, this corresponds to the formation of the
activated enzyme-substrate complex.
Activator
✓ ~~~ An effector molecule that increases the catalytic activity of an enzyme when t
binds to a specific site
Active Center
✓ ~~~ That part of enzyme or other protein at which the initial binding of substrate and
enzyme occurs to form the intermediate enzyme-substrate complex. Acute Coronary
Syndrome (ACS): A sudden cardiac disorder that varies from angina (chest pain on
exertion with reversible tissue injury), to unstable angina (with minor myocar- dial
injury), to myocardial infarction (with extensive tissue necrosis).
Acute Myocardial Infarction (AMI)
, ✓ ~~~ Gross necrosis of the myocardium as a result of interruption of the blood supply
to an area of the cardiac muscle - it is almost always caused by atherosclerosis of
the coronary arter- ies upon which coronary thrombosis is usually superimposed;
commonly called a "heart attack."
Acute Pancreatitis
✓ ~~~ An acute episode of enzymatic destruction of the pancre- atic substance due to
the escape of active pancreatic enzymes into the pancreatic tissue.
Acute-Phase Reaction
✓ ~~~ The body's response to injury or inflammation, including fever, leukocytosis,
and protein changes.
Acute Porphyrias
✓ ~~~ Inherited disorders of heme biosynthesis, characterized by acute attacks of
neurovisceral symptoms; potentially life threaten- ing; detected by elevated urine
PBG.
Additives
✓ ~~~ Compounds added to bio- logical specimens to prevent them from clotting or to
preserve their constituents.
Adenohypophysis
✓ ~~~ The anterior glan- dular lobe of the pituitary gland. Adrenocorticotrophic
Hormone
(ACTH)
, ✓ ~~~ A 39 amino acid peptide hormone secreted by the anterior pituitary gland that
stimulates the adrenal cortex to secrete cortico- steroids.
Advanced Glycation End Products (AGE)
✓ ~~~ Proteins that have been irre-versibly modified by nonenzymatic attachment of
glucose; may contrib- ute to: the chronic complications of diabetes.
Affinity
✓ ~~~ Energy of interaction of: a single antibody-combining site and its corresponding
epitope on the antigen.
Alcoholic Liver Disease
✓ ~~~ Alcoholic cirrhosis is a condition of irreversible liver disease due to the chronic
inflammatory and toxic effects of ethanol on the liver. The develop- ment of cirrhosis
is directly related to the duration and quantity of alcohol consumption.
Aldolase
✓ ~~~ A glycolytic enzyme that cleaves fructose 1, 6-bisphosphate into
dihydroxyacetone and glyceral- dehyde 3-phosphate.
Aldosterone
✓ ~~~ The major mineralo- corticoid steroid hormone secreted by the adrenal cortex.
It controls salt and water balance in the kidney.
Aliquot
✓ ~~~ A known amount of a homo-geneous material, assumed to be taken with
negligible sampling error (IUPAC); informally, a portion of a specimen such as blood
or urine (n); a process to divide a solution into aliquots (v)
CLINICAL CHEMISTRY
Absorbance (A)
✓ ~~~ The capacity of a sub- stance to absorb radiation; expressed as the logarithm
(log) of the recipro cal of the transmittance (T) of the substance.
Absorption Spectrum
✓ ~~~ The graphical plot of absorbance versus wavelength (the absorbance
spectrum) for a specific compound. Absorptivity: A measure of the absorp- tion of
radiant energy at a given wavelength and/or frequency as it passes through a
solution of a sub- stance at a concentration of 1 mol/L; expressed as the absorbance
divided by the product of the concentration of a substance and the sample path
length.
Accreditation
✓ ~~~ An audit technique that is used to assess the quality of a process by checking
that defined operational standards are being followed, in this case in the
performance of point-of-care testing.
Acid Phosphatase
✓ ~~~ An enzyme of the hydrolase class that catalyzes the cleavage of
orthophosphate from orthophosphoric monoesters under acid conditions.
Acid-Base Balance
✓ ~~~ The homeostatic maintenance of acids and bases within the body to achieve a
physiologic pH (approximately 7.40).
Acid-Base Measurement
, ✓ ~~~ The measure- ment of whole blood pH and blood gases.
Acidemia
✓ ~~~ An arterial blood pH < 7.35.
Acromegaly
✓ ~~~ A chronic disease of adults caused by hypersecretion of pituitary growth
hormone and characterized by enlargement of many parts of the skeleton.
Activation Energy
✓ ~~~ In enzymology, the energy required for a molecule to form an activated
complex. In an enzyme-catalyzed reaction, this corresponds to the formation of the
activated enzyme-substrate complex.
Activator
✓ ~~~ An effector molecule that increases the catalytic activity of an enzyme when t
binds to a specific site
Active Center
✓ ~~~ That part of enzyme or other protein at which the initial binding of substrate and
enzyme occurs to form the intermediate enzyme-substrate complex. Acute Coronary
Syndrome (ACS): A sudden cardiac disorder that varies from angina (chest pain on
exertion with reversible tissue injury), to unstable angina (with minor myocar- dial
injury), to myocardial infarction (with extensive tissue necrosis).
Acute Myocardial Infarction (AMI)
, ✓ ~~~ Gross necrosis of the myocardium as a result of interruption of the blood supply
to an area of the cardiac muscle - it is almost always caused by atherosclerosis of
the coronary arter- ies upon which coronary thrombosis is usually superimposed;
commonly called a "heart attack."
Acute Pancreatitis
✓ ~~~ An acute episode of enzymatic destruction of the pancre- atic substance due to
the escape of active pancreatic enzymes into the pancreatic tissue.
Acute-Phase Reaction
✓ ~~~ The body's response to injury or inflammation, including fever, leukocytosis,
and protein changes.
Acute Porphyrias
✓ ~~~ Inherited disorders of heme biosynthesis, characterized by acute attacks of
neurovisceral symptoms; potentially life threaten- ing; detected by elevated urine
PBG.
Additives
✓ ~~~ Compounds added to bio- logical specimens to prevent them from clotting or to
preserve their constituents.
Adenohypophysis
✓ ~~~ The anterior glan- dular lobe of the pituitary gland. Adrenocorticotrophic
Hormone
(ACTH)
, ✓ ~~~ A 39 amino acid peptide hormone secreted by the anterior pituitary gland that
stimulates the adrenal cortex to secrete cortico- steroids.
Advanced Glycation End Products (AGE)
✓ ~~~ Proteins that have been irre-versibly modified by nonenzymatic attachment of
glucose; may contrib- ute to: the chronic complications of diabetes.
Affinity
✓ ~~~ Energy of interaction of: a single antibody-combining site and its corresponding
epitope on the antigen.
Alcoholic Liver Disease
✓ ~~~ Alcoholic cirrhosis is a condition of irreversible liver disease due to the chronic
inflammatory and toxic effects of ethanol on the liver. The develop- ment of cirrhosis
is directly related to the duration and quantity of alcohol consumption.
Aldolase
✓ ~~~ A glycolytic enzyme that cleaves fructose 1, 6-bisphosphate into
dihydroxyacetone and glyceral- dehyde 3-phosphate.
Aldosterone
✓ ~~~ The major mineralo- corticoid steroid hormone secreted by the adrenal cortex.
It controls salt and water balance in the kidney.
Aliquot
✓ ~~~ A known amount of a homo-geneous material, assumed to be taken with
negligible sampling error (IUPAC); informally, a portion of a specimen such as blood
or urine (n); a process to divide a solution into aliquots (v)
