The concentration of uric acid can be determined in the blood or in the urine. To excess, it is mainly a symptom of gout, too much alcohol consumption or kidney failure.

Uric acid is a waste of the body. Specifically, it is the end product of theexcretion molecules called nucleic acids and purines.

Usually, most of the uric acid in the human body dissolves in the blood and enters the kidneys for elimination in the urine. But in some cases, the body produces excess uric acid or fails to remove enough of it. This condition can be the cause of various disorders.

Uric acid being the end product of the degradation of slurry, its rate varies depending on the purine content in the body. And it turns out that purines are found in particular in food. 

Some of the foods high in purines to avoid are:

• anchovies, herring, mackerel, sardines, shrimps, etc;
• liver, heart, brain, kidneys, sweetbreads, etc;
• peas, dry beans, etc.

The consumption of alcohol, and in particular beer, is not recommended when you want to reduce your uric acid.

On the contrary, among the permitted foods low in purine, we can mention:

• tea, coffee, soft drinks;
• fruits and vegetables ;
• eggs ;
• bread and cereals;
• cheese and more generally dairy products

Why do a uric acid test?

The doctor prescribes a blood test (called uricemia) and / or a urinary uric acid test for:

• detect gout;
• assess how well the kidneys are working;
• it can also be requested in the event of pregnancy;
• or in overweight people.

Note that the analysis of the concentration of uric acid in the urine will also make it possible to better understand the origin of a high level of uric acid in the blood.

In the blood, the normal value of uric acid is between 35 and 70 mg / L.

A higher concentration of uric acid in the blood is called hyperuricemia and can be caused by an overproduction of uric acid in the body or by a decrease in its elimination by the kidneys. So, high levels of uric acid in the blood can be a sign of:

• gout (this is the main cause of an increase in the level of uric acid in the blood);
• an excess of degradation of the proteins of the organism which takes place, for example, during chemotherapy, leukemia or even lymphoma;
• alcoholism;
• excessive physical exercise;
• the presence of kidney stones;
• rapid weight loss;
• diabetes;
• a diet rich in purine;
• preeclampsia during pregnancy;
• or kidney failure.

On the contrary, it is possible that the blood uric acid level is lower than normal, but this is a rarer condition than the scenario where it ends up higher.

Thus, uric acid levels below normal values ​​may be related to:

• a low-purine diet;
• Wilson’s disease (a genetic disease in which copper builds up in the body);
• kidney (such as Fanconi syndrome) or liver damage;
• or even exposure to toxic compounds (lead).

In urine, the normal value of uric acid is between 250 and 750 mg / 24 hours.

Note that normal values ​​may vary slightly depending on the laboratories performing the analyzes.

Affecting 5 to 15% of the population, it is a common biochemical abnormality, resulting from an overproduction of uric acid and / or reduced renal elimination. It often develops painlessly and is therefore not always immediately diagnosed.

High uric acid levels can be explained by:

Idiopathic or primary hyperuricemia

They represent the vast majority of cases. Hereditary predispositions are found in 30% of subjects, but they are often associated with obesity, overeating, high blood pressure, alcohol abuse, diabetes and hypertriglyceridemia.

Rare enzyme abnormalities

They are found in particular in Von Gierke disease and Lesch-Nyhan disease. These enzymatic abnormalities have the particularity of causing gout attacks very early on, ie in the first 20 years of life.

Hyperuricemia secondary to disease or drug treatment.

These hyperuricemia may be due to:

– a lack of elimination of uric acid. This is the case for kidney failure, but also because of certain drugs (diuretics, but also laxatives and some anti-tuberculosis drugs).

– an increase in the degradation of nucleic acids. We see this in blood diseases (leukemia, hemopathies, hemolytic anemia, extensive psoriasis), and in the consequences of certain cancer chemotherapies.

The consequences of hyperuricemia

Hyperuricemia can cause two types of problems:

• Gout responsible for inflammatory-type joint pain.

When the microcrystals of uric acid dissolved in the blood are in too high a concentration and the local conditions are favorable (in particular a sufficient acidity of the medium), they precipitate and lead to local inflammation. This preferentially affects the joint of the big toe. Only 1 in 10 people with too much uric acid in their blood will get gout, so you need extra susceptibility to get it.

• Urinary lithiasis.

They are due to the presence of one or more stones in the urinary tract and are responsible for renal colic. Urolithiasis is a very common disease since 1 to 2% of the population is affected in France.

The analysis of the level of single acid can be carried out in the blood and / or in the urine:

• the blood test consists of a sample of venous blood, usually in the crease of the elbow;
• the level of uric acid in the urine is measured over 24 hours: to do this, it is sufficient to urinate in a container provided for this purpose and provided by medical personnel for one day and one night.

Note that it is advisable not to eat or drink anything during the hours preceding the test.

There are many factors that can affect the level of uric acid in the blood or in the urine. These include:

• foods (poor or high in purines);
• drugs (to sign gout, aspirin, or even diuretics);
• age, children with lower values;
• gender, with women generally having lower rates than men;
• weight, obese people having a higher rate.

Drug treatments if the hyperuremia is symptomatic are as follows: 

• Nucleic acid synthesis reducers, such as allopurinol. You have to be very vigilant because there are many interactions with other drugs.
• Medicines that inhibit renal uric acid reabsorption, such as benzbromarone.
• Enzymatic treatments which often cause allergy problems.

Whatever happens, it is the doctor who must decide whether a treatment should be followed, and which is the most suitable.