Total protein: what it is, what it tells you and when it’s tested

Total protein is the sum of the proteins in your blood. More than half is albumin, made by your liver. The rest are globulins, antibodies among them. They keep water inside your blood vessels, carry substances and fight infection.

When it’s tested

Doctors often order it in routine blood tests, next to albumin. They also ask for it with swollen legs, weight loss, lasting diarrhoea, or to follow liver or kidney disease.

On its own it says little: it is a sum. If it changes, the question is whether albumin fell or globulins rose. So your doctor looks at albumin and, if needed, protein electrophoresis.

That is why Rosa does not test total protein. Instead it measures albumin, the largest part, together with liver enzymes, creatinine and a urine test.

What it tells you, and what it does not

If it is low, albumin has usually fallen: the liver makes too little, or it is lost through the urine or the gut.

If it is high, you often drank too little. If it stays high, the globulins have usually risen, from inflammation or an infection that lasts.

It does not show which protein changed. That needs albumin and protein electrophoresis.

That is why it is read together with other tests:

• Albumin: It is more than half of total protein
• Protein electrophoresis: It shows which protein changed
• ALT and AST: They show whether the liver is under strain
• Urine test: It shows whether protein is lost in the urine

Normal total protein levels

The lab decides what is normal. Many lab reports give 6.4 to 8.3 g/dL. Your own report may print slightly different limits.

Some labs use g/L: the number is ten times larger, for example 64 to 83 g/L.

The blood test is usually done fasting. If you drank too little, values can be a little higher.

What your result means

Find the row for your result, in g/dL. If your report uses g/L, divide by ten. Which values need a doctor? Below 6.4 or above 8.3, especially if your albumin is out of range.

• Below 6.4: Low. Your body makes too little protein or loses too much. Albumin is often behind it, which can fall because of the liver, kidneys, gut or a poor diet. Talk to your doctor: they usually look at albumin, liver tests and a urine test.
• 6.4 to 8.3: Normal. Your blood proteins are at the right level. Nothing to do.
• Above 8.3: High. Often you drank too little or the tourniquet stayed on a long time. If they stay high, the globulins are usually up, from inflammation that lasts. Talk to your doctor: they usually repeat the test and, if needed, order protein electrophoresis.

If your total protein is high or low

• Low total protein: Albumin has usually fallen. The cause is looked for in the liver, kidneys, gut or diet.
• High total protein: Often too little water. If it stays high, your doctor looks at the globulins with electrophoresis.

Causes of low or high total protein

The most common, in each direction.

• Low: the liver: Liver disease, such as cirrhosis, means less albumin is made.
• Low: the kidneys: Some kidney diseases make you lose protein in your urine, which turns foamy.
• Low: the gut: Coeliac disease and other gut conditions mean you absorb too little or lose protein.
• Low: eating too little: A very poor diet, a long fast or an eating disorder.
• High: drinking too little: With less water in the blood, everything is more concentrated. It settles once you drink.
• High: inflammation or infection that lasts: Hepatitis B or C, HIV or autoimmune diseases make the body produce more antibodies.
• High: one protein in excess: Less often, a single group of cells makes too much of one protein. Electrophoresis shows it.

Symptoms of low total protein

If it falls a little, there are usually no symptoms. If it falls a lot, albumin especially, these can appear:

• Swelling of the ankles, legs or around the eyes
• Very foamy urine
• Tiredness and weight loss for no reason
• Lasting diarrhoea, if the gut is involved

If your legs are swollen and you suddenly get short of breath, call 112 or go to the emergency department.

What to do if your total protein is low

It depends on the cause. Where to start:

• First, with your doctor, look at albumin, liver tests and a urine test: they show where to look.
• If you eat little or follow a very restrictive diet, talk to your doctor or a dietitian.
• Do not take protein supplements on your own if you have kidney or liver disease: ask your doctor first.

If the cause is the liver, kidneys or gut, your doctor decides the treatment. Eating more protein alone is not enough.

What can skew the result

A few things change it without any disease. It helps to know them before your blood test.

• Drinking too little: With little water in the blood, protein looks higher.
• A tourniquet left on too long: If the tourniquet stays tight for minutes, protein rises a little. That is a detail of the draw, not yours.
• A lot of fluid through a drip: In hospital, many drips dilute the blood and lower it.
• Fasting: The blood test is usually asked fasting, together with your other tests.

When to worry

Talk to your doctor if:

• Your total protein is below 6.4 or above 8.3 g/dL, especially if your albumin is out of range too.
• It stays out of range when you repeat the test.
• Your ankles or eyes are swollen, or your urine is very foamy.
• You are losing weight for no reason, or have diarrhoea or tiredness that lasts.
• You have new bone pain, frequent infections or unexplained anaemia.
• Your legs are swollen and you suddenly get short of breath: call 112 or go to the emergency department.

Frequently asked questions

What are normal total protein levels? Many lab reports give 6.4 to 8.3 g/dL, that is 64 to 83 g/L. The range on your own report is what counts.

Low total protein: what does it mean? Usually that albumin has fallen. The most common causes are the liver, kidneys that leak protein, the gut or a poor diet. Your doctor starts with albumin and a urine test.

High total protein: should I worry? Just above the limit, it often means you drank too little. If it stays high, your doctor orders electrophoresis to see which proteins rose.

What is the difference between total protein and albumin? Albumin is a single protein, the most abundant one. Total protein is albumin plus all the globulins. Take albumin away and what is left is the globulins.

Does eating more protein raise blood protein? Only a little, if you already eat enough. The value depends mostly on the liver, kidneys and gut. Diet matters more when it is really poor.

Does Rosa test total protein? No. Rosa measures albumin, more than half of it, and liver enzymes, creatinine and a urine test. If your doctor wants total protein, they order it separately.

Sources

• MedlinePlus, U.S. National Library of Medicine: Total protein test. MedlinePlus, Total protein
• Busher, serum albumin and globulin. In: Clinical Methods: the history, physical, and laboratory examinations. Butterworths, 1990. PMID 21250048
• Lippi and colleagues, influence of short-term venous stasis on clinical chemistry testing. Clinical Chemistry and Laboratory Medicine, 2005. PMID 16201899
• O’Connell and colleagues, understanding and interpreting serum protein electrophoresis. American Family Physician, 2005. PMID 15663032