What is albumin?

Albumin is any protein that is soluble in water and moderately concentrated salt solutions, and is coagulable by heat. Albumin is the most abundant plasma protein found in the body, it is formed principally in the liver and constitutes up to two third of the 6 to 8 percent protein concentration in the plasma. Albumin is responsible for much of the colloidal osmotic pressure of the blood, and hence is a very important factor in regulating the exchange of water between the plasma and the interstitial compartment, which is the space between the cells. Due to the hydrostatic pressure, water is forced through the walls of the capillaries in the tissue space. This flow of water is continuous until the osmotic pull of protein, in this case albumin molecules, causes it to stop. A drop in the quantity of albumin in the plasma leads to an increase in the flow of water from the capillaries into the interstitial compartment, and this then leads to an increase in tissue fluid, which if sever enough, becomes apparent as edema. Albumin also serves as a transport protein carrying large organic anions, those such as fatty acids, hormones (cortisol and thyroxine when their specific binding globulins are saturated), bilirubin and many drugs.

Albumin has three main functions, which are as follows; transport metabolites (such as bilirubin, free fatty acids, and thyroid hormones), keep the oncotic pressure (fundamental function for the distribution of liquids in the capillaries and tissues of the human body), and can be used as amino acids by the body if need be.

Various albumins are found in practically all animal tissues and in many plant tissues.


Why measure the level of albumin?

This test allows us to obtain useful and critical information on the liver and kidney function of the patient being examined. The presence of albumin in the urine, known as albuminuria, indicates that the patient may have malfunction of the kidney, and may accompany kidney diseases and heart failure. A person with sever 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 within the human body, 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.

This test can help determine if a patient has liver disease or kidney disease, or if the body is not absorbing enough proteins.


Standard of preparation

Sampling is usually done in the morning in the hospital. The doctor will recommend if you need to be fasting prior to the examination. It is also very important that you inform your doctor of any medication you are currently taking, as certain drugs may interfere with the results of the exam. Drugs that can increase albumin levels are as follow, anabolic steroids, growth hormones, androgens, and insulin. However do not stop taking your medication without prior recommendation from a doctor. Make sure to inform your doctor of any prior medical history.


Is the exam painful or dangerous?

The examination is neither dangerous nor painful. The patient may feel a slight tingling sensation, with the entrance of the needle in the arm.


How is the exam performed?

The examination is done by a simple blood test.