The uric acid test measures the amount of uric acid in blood or urine. Uric acid is a waste product from the metabolism of a class of chemicals known as purines which are found both in our own cells and in foods we eat.
High levels of uric acid in blood may lead to the formation of uric acid crystals in your joints, a condition known as gout. Moreover, being excreted from the body by the kidneys, high levels of uric acid may also cause uric acid stones and kidney damage. Lastly, hyperuricemia is also a risk factor for metabolic syndrome and cardiovascular disease.
Normal levels of uric acid in blood and urine
Normal values for all tests vary from lab to lab, so the normal reference range on your results for uric acid may be slightly different than the ones below.
- Adult male: 4.0-8.5 mg/dL or 0.24-0.51 mmol/L
- Adult female: 2.7-7.3 mg/dL or 0.16-0.43 mmol/L
In urine normal levels are:
- 250-750 mg/24 hr or 1.48-4.43 mmol/day
What Causes high uric acid levels?
Increased production of uric acid may be caused by the following two factors:
- The body makes too much uric acid.
- The kidneys don’t eliminate enough uric acid.
A diet with too many purine-rich foods, a high calorie diet, drinking too much alcohol, cancer treatment such as chemotherapy and radiotherapy are all possible causes of increased production or uric acid. You may also have the tendency to have high uric acid levels due to inherited genetic factors.
Kidney disease, certain types of diuretic medications, and hypothyroidism are some of the possible causes of decreased excretion of uric acid through urine.
How is gout diagnosed?
Having high uric acid levels is not how gout is diagnosed: when you have too much uric acid in blood it is a state called hyperuricemia and this condition, if left untreated, can cause gout.
Gout is diagnosed when uric acid crystals are found in fluid samples taken from swollen joints (arthrocentesis) or when the crystals are seen by diagnostic imaging such as an MRI, ultrasounds or CT scan.
Food high in purine content
If you have the tendency to have high uric acid levels or if you have been diagnosed with gout, you should try to avoid certain foods and drinks that are high in purine content to lower the chance of a gout attack and decrease uric acid in blood. If you are overweight, you should also decrease the overall calorie intake and increase physical activity in an effort to lose some weight; you should lose weight in a gradual and controlled manner, no more than 1-2 lbs or 1 kg per week, as fasting or other fast weight loss practices may actually increase uric acid in the short term.
Red meat, goat and pork should be avoided or very limited in your diet. Organ meats in particular such as liver are high in purines and should not be in your diet.
Seafood and in particular sardines, anchovies, herrings, trout, tuna and shellfish also have medium to high purine content.
Food and drinks high in fructose such as mangoes, honey, corn syrup, sodas and fruit juices increase serum uric acid.
Alcohol should be avoided completely or be very limited. Non-alcoholic beer contains yeast and for this reason should be avoided as well.
Mushrooms, spinach, cauliflower and other vegetables contain moderate to high amounts or purines as you may read from several sources, but according to studies they are not likely to cause gout attacks or to increase significantly uric acid levels.
What foods are best to eat when having high uric acid levels?
Vegetable proteins should be your main source of proteins. Soy, lentils, beans, peas and tofu are all good alternatives to meat. Eggs can be a good source of proteins as well.
Fats and oils, nuts, grains can all be eaten.
Low-fat dairy products such as skim milk and low-fat yogurt seem to decrease the risk of gout.
Fruits and vegetables are all good, with the exception of high fructose fruits such as grapes and mangoes. Fruit high in vitamin C like citrus, strawberries, and kiwis help lower uric acid levels.
Drink plenty of water unless otherwise directed by your doctor. If you are already drinking 8 glasses of water per day, you may increase the daily intake by a few glasses.
Treatment for high uric acid
High uric acid levels generally only require lifestyle interventions unless you have been diagnosed with gout and had gout attacks in the past or you have kidney disease.
Lifestyle interventions include diet and exercise to maintain a healthy weight, drinking plenty of water, avoiding sugary drinks, eat a low-purine diet, avoiding alcohol.
The most commonly used medication to prevent gout episodes and lower uric acid levels is allopurinol; other medications that may be administered in some cases are probenecid and febuxostat. Pegloticase is an IV medication used only in patients that do not tolerate other treatments.
In case of an acute gout attack NSAIDs and topical application of ice may help ease pain and inflammation. Colchicine and steroids are also commonly used in the management of acute attacks.
When large uric acid crystals form inside the joints or when joint have been compromised by gouty arthritis, surgical removal of the crystals or joint replacement surgery may be indicated.
- High plasma uric acid concentration: causes and consequences.
EP de Oliveira – Diabetology and Metabolic Syndrome, Apr 2012
- Purine-Rich Foods, Dairy and Protein Intake, and the Risk of Gout in Men.
HK Choi – The New England Journal of Medicine, Mar 2004
- Purine-rich foods, protein intake, and the prevalence of hyperuricemia: The Shanghai Men’s Health Study.
R Villegas et al – Nutrition, Metabolism & Cardiovascular Diseases, May 2012
- Mosby’s Diagnostic & Laboratory Test Reference, 14th edition
K Pagana – Elsevier, 2018
- National Kidney Foundation