albumin-globulin ratio

(redirected from A/G r)
Also found in: Encyclopedia.


1. any protein that is soluble in water and moderately concentrated salt solutions and is coagulable by heat.
2. serum albumin; the most abundant plasma protein, formed principally in the liver and constituting up to two thirds of the 6 to 8 per cent protein concentration in the plasma. (See accompanying table.) Albumin is responsible for much of the colloidal osmotic pressure of the blood, and thus is a very important factor in regulating the exchange of water between the plasma and the interstitial compartment (space between the cells). Because of hydrostatic pressure, water is forced through the walls of the capillaries into the tissue spaces. This flow of water continues until the osmotic pull of protein (albumin) molecules causes it to stop. A drop in the amount of albumin in the plasma leads to an increase in the flow of water from the capillaries into the interstitial compartment. This results in an increase in tissue fluid which, if severe, becomes apparent as edema. Albumin serves also as a transport protein carrying large organic anions, such as fatty acids, bilirubin, and many drugs, and also hormones, such as cortisol and thyroxine, when their specific binding globulins are saturated.

The presence of albumin in the urine (albuminuria) indicates malfunction of the kidney, and may accompany kidney disease or heart failure. A person with severe renal disease may lose as much as 20 to 30 g of plasma proteins in the urine in one day.

A decrease in the serum albumin level may occur with severe disease of the kidney. Other conditions such as liver disease, malnutrition, and extensive burns may result in serious decrease of plasma proteins.
albumin-globulin ratio the ratio of albumin to globulin in blood serum, plasma, or urine.
albumin human a preparation of human serum albumin, used as an artificial plasma extender and to increase bilirubin binding in hyperbilirubinemia.
iodinated I 125 albumin a radiopharmaceutical used in blood and plasma volume, circulation time, and cardiac output determinations, consisting of albumin human labeled with iodine-125.
iodinated I 131 albumin a radiopharmaceutical used in blood pool imaging and plasma volume determinations, consisting of albumin human labeled with iodine-131.
normal human serum albumin albumin human.
serum albumin albumin of the blood.


 [ra´she-o] (L.)
an expression of the quantity of one substance or entity in relation to that of another; the relationship between two quantities expressed as the quotient of one divided by the other.
A/D ratio adult versus developmental toxicity ratio; the ratio between the toxic effects of a substance on adults (humans or animals, especially pregnant females) and such effects on developing embryos or fetuses.
A-G ratio (albumin-globulin ratio) the ratio of albumin to globulin in blood serum, plasma, cerebrospinal fluid, or urine.
arm ratio a figure expressing the relation of the length of the longer arm of a mitotic chromosome to that of the shorter arm.
benefit-risk ratio a determination of the potential of a research study for positive effects on patients compared to the risks of doing harm.
cardiothoracic ratio on a chest radiograph, the ratio of the transverse diameter of the heart to the internal diameter of the chest at its widest point just above the dome of the diaphragm.
grid ratio a ratio comparing the height of lead lines in an x-ray grid to the distance between the lead strips.
inspiratory-expiratory ratio the ratio of the inspiratory time to the expiratory time during the breathing cycle. Normally, expiratory time will be longer than inspiratory time; if the inspiratory time is longer than the expiratory time, gas trapping may result.
lecithin/sphingomyelin ratio see lecithin-sphingomyelin ratio.
risk ratio relative risk.
sex ratio the proportion of one sex to the other; by tradition the number of males in a population to the number of females, usually stated as the number of males per 100 females.
signal-to-noise ratio the ratio between the amplitude of a signal being measured and that of the noise.
urea excretion ratio the ratio of the amount of urea in the urine excreted in one hour to the amount in 100 ml of blood. The normal ratio is 50.
zeta sedimentation ratio (ZSR) a measurement comparable to the erythrocyte sedimentation rate, except that it is unaffected by anemia. The packed-cell volume (zetacrit) of a blood specimens is calculated by centrifuging the specimen in a Zetafuge, a specially designed instrument that produces controlled cycles of compaction and dispersion and allows rouleaux to form and sediment rapidly. The zetacrit divided into the true hematocrit gives the zeta sedimentation ratio.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

albumin-globulin ratio


A/G r

The ratio of albumin to globulin in blood plasma or serum. Normally this value is 1.3:1 to 3.0:1.
Medical Dictionary, © 2009 Farlex and Partners