what is uric acid? Uric acid analysis
The concentration of uric acid can be determined in the blood or in the urine. To excess, it is mostly a symptom of gout , excessive consumption of alcohol or kidney failure.
What is uric acid, blood or urine?
Uric acid is a waste of the body. More precisely, it is the final product of the excretion of molecules called nucleic acids and purines.
Generally, most of the uric acid in the human body dissolves in the blood and joins the kidneys to be eliminated in the urine. But in some cases, the body produces an excess of uric acid or fails to eliminate enough. This condition can cause various disorders.
Uric acid and nutrition
Since uric acid is the end product of purine degradation, its level varies with the level of purine in the body. And it turns out that purines are found in particular in the diet.
Some foods rich in purines to avoid:
- anchovies, herring, mackerel, sardines, shrimps, etc .;
- liver, heart, brain, kidneys, sweetbreads, etc .;
- peas, dried beans, etc.
Consumption of alcohol, especially beer, is not recommended when you want to reduce uric acid.
On the contrary, among the permitted foods that are low in purine are:
- tea, coffee, soft drinks;
- fruits and vegetables ;
- eggs ;
- bread and cereals;
- cheese and more generally dairy products
Why do a uric acid analysis?
The doctor prescribes a blood test (we speak of uricemia) and/or a urine dosage of uric acid for:
- detect gout;
- evaluate the functioning of the kidneys;
- it can also be requested in case of pregnancy;
- or in overweight people.
It should be noted that the analysis of the uric acid concentration in the urine will also make it possible to better understand the origin of a high level of uric acid in the blood.
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| what is uric acid? Uric acid analysis |
Blood test for uric acid
In the blood, the normal value of uric acid is between 35 and 70mg / L.
A higher concentration of uric acid in the blood is called hyperglycemia and can be caused by over-production of uric acid in the body or by a decrease in its elimination by the kidneys. Thus, high levels of uric acid in the blood can be a sign of:
- gout (this is the main cause of an increase in uric acid levels in the blood);
- an excess of degradation of the proteins of the organism which takes place for example during chemotherapies, leukemia or lymphomas;
- alcoholism;
- an excess of physical exercise;
- the presence of kidney stones;
- fast weight loss;
- diabetes;
- a diet rich in purine;
- preeclampsia during pregnancy;
- or kidney failure.
On the contrary, it is possible that the level of blood uric acid is lower than normal, but it is a rarer condition than the scenario where it is found higher.
Thus, uric acid levels below normal values can be related to:
- a diet low in purines;
- Wilson's disease (a genetic disease characterized by a buildup of copper in the body);
- kidney (such as Fanconi syndrome) or hepatic impairment
- or 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 that perform the analyzes.
Affecting 5 to 15% of the population, it is a common biochemical abnormality, resulting from overproduction of uric acid and/or decreased renal elimination. It often develops without pain and is therefore not always immediately diagnosed.
search also for gout, high uric acid, uric acid level, uric acid test, what is uric acid
High levels of uric acid can be explained by:
Idiopathic or primitive 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 enzymatic abnormalities
They are found especially in Von Gierke's disease and Lesch-Nyhan's disease. These enzymatic abnormalities have the particularity of generating gout crises very early, that is to say in the first 20 years of life.
Hyperuricemia secondary to a disease or a drug treatment.
This hyperuricemia may be due to:
- a defect 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-TB drugs).
- a defect 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-TB drugs).
an increase in the degradation of the nucleic acids. This is seen in blood diseases (leukemias, hemopathies, hemolytic anemias, extensive psoriasis), and in the aftermath of certain cancerous chemotherapies.
The consequences of hyperuricemia
Hyperuricemia can cause two types of problems:
- Gout responsible for the joint pain of the inflammatory type.
When the microcrystals of uric acid dissolved in the blood are in too high concentration and the local conditions are favorable (including sufficient acidity of the medium), they precipitate and cause local inflammation. This preferably affects the articulation of the big toe. Only 1 in 10 people who have too much uric acid in the blood will become gouty, so you need extra susceptibility to getting it.
- Urinary lithiasis.
They are due to the presence of one or more stones in the urinary tract and are responsible for nephritic colic. Urolithiasis is a very common disease since 1 to 2% of the population is affected in France.
How is the analysis done?
The analysis of the single acid level can be carried out in the blood and/or in the urine:
- the blood test consists of a venous blood sample, usually in the fold of the elbow;
- the uric acid level in the urine is measured for 24 hours: to do this, it is sufficient to urinate in a container provided for this purpose and provided by the medical staff for a day and a night.
Note that it is advisable not to drink or eat anything during the hours preceding the test.
What are the factors of variation?
Many factors are likely to vary the level of uric acid, in the blood or in the urine. These include:
- foods (poor or high in purines);
- medicines (to sign gout, aspirin, or diuretics);
- age, children with lower values;
- sex, with women, generally having lower rates than men;
- weight, obese people with a higher rate.
The drug treatments if the hyperuricemia is symptomatic are as follows:
- Nucleic acid synthesis reducers, such as allopurinol. You have to be very careful because there are many interactions with other drugs.
- Drugs that inhibit the renal reabsorption of uric acids, such as benzbromarone.
- Enzymatic treatments that often pose allergy problems.
Whatever happens, it is the doctor who must decide whether a treatment should be followed, and which is the most appropriate.
