Liver and pancreas
Totaal eiwit
The total amount of protein in the blood, mainly albumin and antibodies; a rough measure of nutrition, liver, kidneys and immune system.
Everything about this testWhat it measures
Total protein is the sum of all proteins in the blood. Most of it is albumin, which is made by the liver. The rest are globulins: a large group of hundreds of proteins, including transport proteins, clotting proteins and antibodies (immune proteins). The value changes if the blood is concentrated or diluted, if the liver makes less albumin, if the body loses protein through the kidneys or the bowel, or if the immune system makes more antibodies.
- Dehydration (the value is then raised)
- Severe malnutrition, protein loss through the kidneys or the bowel, or reduced production by the liver in advanced liver disease (cirrhosis)
- More antibodies in the blood with long-lasting inflammation, chronic infection or liver disease
- Rarely: an M-protein, which is one type of antibody that is made in large amounts
High
A slightly raised total protein is usually caused by dehydration: drinking too little, sweating, diarrhea or vomiting. Leaving the tourniquet on for a long time during the blood draw also gives a slightly higher value. With long-lasting inflammation, a chronic infection such as hepatitis or a liver disease, the immune system makes more antibodies; total protein then rises while albumin is normal or low. Rarely: an M-protein, one type of antibody that is made in large amounts, usually in MGUS (a condition without symptoms) and very occasionally in Kahler's disease (multiple myeloma). According to the Dutch Society for Clinical Chemistry (NVKC), it is mainly a markedly raised value that calls for further tests.
Low
A low total protein is usually caused by a low albumin. Possible causes are severe malnutrition, protein loss through the kidneys (there is then a lot of protein in the urine and fluid builds up in the legs) or through the bowel, and advanced liver disease. During a severe infection, in pregnancy and after drinking a lot of water, the value can be temporarily lower. Rarely, a low value is caused by a shortage of antibodies; this often goes with recurring infections. A slightly low value without symptoms usually has no meaning.
If your result is abnormal
With an abnormal total protein, the GP usually has albumin measured and repeats the measurement, preferably without dehydration or illness. If total protein is raised while albumin is normal, protein electrophoresis often follows to see which protein group is raised. With a low value, tests of the kidneys (protein in the urine), the liver and nutrition follow.
Reliability
Total protein is a rough, non-specific value: an abnormality does not say which protein is too high or too low. According to the Dutch Society for Clinical Chemistry (NVKC), other tests, such as albumin and protein electrophoresis, must first show which protein group is abnormal before anything can be said about the cause. Total protein is not a good measure of how much protein you eat: in healthy people the value stays normal even with a vegetarian or vegan diet, and only falls with severe malnutrition. In people without symptoms, a single value says little; with an abnormality, albumin and protein electrophoresis say more.
Limitations
- Dehydration, leaving the tourniquet on for a long time during the blood draw and standing just before the blood draw raise the value; lying down for a long time and drinking a lot just before the blood draw lower it.
- With a finger prick, squeezing hard can mix in tissue fluid, which makes the result lower and less reliable.
- An infection, inflammation or pregnancy temporarily changes the value.
- Serum and plasma give slightly different values; reference values differ between laboratories.
How common is this
A clearly abnormal total protein in healthy adults without symptoms is unusual; most abnormalities are slight and are caused by dehydration or the blood draw. A protein shortage due to diet is rare in the Netherlands: according to the Netherlands Nutrition Centre (Voedingscentrum), most people get enough protein, including vegetarians and athletes, and mainly older people are at risk of malnutrition. An M-protein occurs in about 3 in 100 people over 50, usually without total protein being abnormal.
Who is this useful for
Useful as part of tests of the liver, kidneys or nutritional status, with fluid in the legs without a clear cause, with unintended weight loss and as a first step to investigate an abnormal protein distribution further. As a check of protein intake with a vegetarian or vegan diet, the test says little, because the value almost always stays normal in healthy people. In healthy adults without symptoms, a stand-alone test adds little.
Downsides and risks
- A slightly abnormal value due to dehydration or the blood draw can lead to unnecessary worry without a repeat measurement.
- Further tests for a raised value can find an M-protein without symptoms (MGUS), which needs no treatment but can lead to years of check-ups.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results