Albumin blood test: normal range and what the result means

Albumin makes up more than half of the proteins in blood plasma. It has two main jobs: keeping water inside the blood vessels (oncotic pressure — when albumin is short, fluid moves into the tissues and swelling appears) and carrying substances — hormones, bilirubin, calcium, fatty acids and many medicines. Albumin is made only by the liver, so it is a marker of liver synthesis: in cirrhosis it falls. In a healthy body the kidneys do not let albumin through — when it appears in the urine, that is a sign of kidney damage (albumin in urine). Albumin also falls in chronic inflammatory diseases, when protein is short (an inadequate diet, coeliac disease, Crohn's disease) and after operations. Albumin stays in the blood for a long time, so it shows not the state of today but that of a longer period. Albumin matters when assessing calcium: about half of the calcium is bound to albumin, so when albumin is low, total calcium looks decreased.

• When liver disease is suspected — as part of the liver tests
• When kidney disease is suspected — together with albumin in the urine
• When there is swelling, especially of the legs and around the eyes
• To assess nutritional status — in chronic illness, after operations, in older age
• When absorption in the gut is poor — coeliac disease, Crohn's disease
• When interpreting a calcium result

A raised albumin almost always means dehydration — the blood thickens and the concentration of the protein rises. Other causes are a very high amount of protein in food, and a tourniquet left tight on the arm for a long time during the blood draw. There is no true disease of albumin excess.

Causes of raised albumin

• Dehydration
• A diet high in protein
• A tourniquet left tight on the arm for a long time during the blood draw
• Disturbances of water balance

What to discuss with a doctor

• Whether you drink enough — the most common cause
• Repeating the test when well hydrated

Lowered albumin

A lowered albumin shows that the liver is making too little of it (hepatitis, cirrhosis), that the kidneys are losing it (kidney diseases), that the body is not getting or not absorbing protein (an inadequate diet, coeliac disease, Crohn's disease, Whipple's disease), or that there is chronic inflammation. A low albumin causes swelling and changes the calcium and medicine readings.

• Liver diseases — hepatitis, cirrhosis
• Kidney diseases — albumin is lost in the urine
• An inadequate diet, low in protein
• Poor absorption — coeliac disease, Crohn's disease, Whipple's disease
• Chronic inflammatory diseases, infections
• The state after operations, burns

Symptoms that can occur with low albumin

• Swelling — of the legs, around the eyes, of the abdomen
• Tiredness, weakness
• Slow-healing wounds

What to discuss with a doctor when albumin is low

• Liver markers — ALT, AST, bilirubin, clotting
• Albumin and creatinine in the urine — whether the kidneys are losing protein
• Nutritional status and diseases of the gut
• CRP — whether the cause is inflammation
• Corrected calcium, if calcium looks decreased

Albumin and calcium

About half of the calcium in the blood is bound to proteins, mostly to albumin (MedlinePlus medical encyclopedia: Calcium blood test). When albumin is low, total calcium looks decreased even though the active part may be normal — so laboratories calculate corrected calcium or measure ionised calcium. That is why albumin is also tested when a calcium result is being interpreted.

Reading the result

Albumin stays in the blood for a long time, so it shows the state of a longer period rather than that of a single day. It is not read on its own: when albumin is low, a doctor usually assesses the liver markers, the urine test, CRP and nutritional status, and whether there is any swelling. More on results in general: how to read blood test results.