Albumin is an important protein manufactured in the liver, which circulates in the blood stream. Human albumin is a pale. somewhat sticky material, quite like the white of an egg. In certain disorders albumin may pass through the small blood vessels of the kidney and appear in the urine. One of the basic tests in medicine is, therefore, the test for albuminuria – the presence of albumin in urine. Here albumin may he found as a result of acute or chronic inflammation of the kidneys: as a result of the effect of high blood pressure on the kidneys, or in circulatory disorders affecting the kidneys, such as heart failure.
Some drugs and poisons may damage the kidneys sufficiently to produce albuminuria. This condition may also be due to quite innocuous causes, such as fever. In a few individuals, albumin appears in the urine when they assume the upright position, although not present when they are lying down. This is known as orthostatic albuminuria: it is of no great concern but may lead to diagnostic difficulties. One of the few threatening disorders associated with pregnancy, known as eclampsia, has various warning symptoms and findings, such as rise in blood pressure, headache. and puffiness around the eyes and elsewhere. Generally associated with these is the finding of albumin in the urine. Eclampsia illustrates one of the reasons for doing routine urinalysis during pregnancy.
One rather serious affliction of the kidneys-the nephrotic syndrome-results from various kinds of inflammations and also from advanced diabetes: large amounts of albumin are poured out into the urine and because of the loss of this important protein, marked swelling of the various tissues (edema) occurs. The major change that underlies all forms of this disorder is loss of albumin into the urine.