Everything You Need To Know About Blood Test For Gout

If you’re not familiar with gout, its clinical features or any related medications for gout, then, the term blood test for gout may sound new to you.

A blood test for gout (also known as uric acid blood test or serum uric acid measurement) measures the amount of uric acid (urate) in your blood.

The test determines how well is the production and removal of uric acid by your body.

Blood Test Tubes

You need this test when you have elevated levels of uric acid (hyperuricemia).

The uric acid blood test is a common blood test for gout sufferers and those at potential risk of developing gout.

As mentioned by Dalbeth et al., the prevalence of gout in Aotearoa, New Zealand is very high, affecting 3.8% of those above the age of 20.

In other words, gout is a disease that needs to be treated as it can happen at younger ages.

Thus, understanding the role of this blood test for gout is crucial.

Herein, we provide knowledge regarding the uric acid blood test, focusing on the use of this test for gout patients and those with a high risk of developing gout.

What Is Being Tested?

Typically, one of those waste products sends away by your body is uric acid. 

It is produced when your body breaks down chemicals called purines. The blood test for gout measures the level of uric acid in the blood.

The body gets rid of uric acid when you urinate. Uric acid can build up in the blood if there’s too much production of uric acid or your kidney aren’t performing well.

It can make crystals that can form and collect in the joints. This causes painful inflammation in and around the joints, a condition known as gout.

Why Urate Testing?

As mentioned before, you need this test if you experienced elevated levels of uric acid.

Your doctor may advise this test when your diagnosis of gout is under consideration.

According to the University of Rochester Medical Center, symptoms of gout include:

  • Joint pain or soreness
  • Swelling and pain especially in the big toe, ankle, or knee
  • Joints that feel warm when touched 
  • Swelling and pain affecting one of the joint in the body
  • Reddish, shiny skin around the joints 

Why Do I Need To Do Blood Test For Gout?

Monitoring of gout treatment depends largely on the level of urate in the blood. Effective management of gout required a long-term lowering of the uric acid level.

The target concentration of urate level as recommended by both the American College of Rheumatology and the European League Against Rheumatism for patients under urate-lowering therapy is less than 0.36 mmol/L.

This target is a requisite to achieve urate crystal dissolution in vivo, prevent gout attacks, and allow regression of tophi.

According to Dalbeth et al., the velocity of tophus regression is inversely related to the blood urate concentration.

Thus, for those with a severe tophaceous disease, a lower target of less than 0.30mmol/L may be necessary.

Needless to say, performing a blood test for gout is part of gout management.

Monitoring of the level of urate in the blood is crucial in ensuring relevant treatment target are achieved by patients.

When Should Urate Be Tested?

Based on their report, Dalbeth et al. stated that uric acid blood test can be conducted non-fasting at any time of the day.

To establish the diagnosis of gout, testing should be repeated for cases in which urate level is not elevated at the time of gout attack, and the diagnosis of gout remains a possibility.

For gout sufferers, urate should be measured frequently, during the initiation and escalation of urate-lowering therapy.

To ensure ongoing maintenance of urate control, testing should be performed every 6–12 months once the target urate level is achieved.

Preparation For The Test

Before taking the blood test for gout, consult your doctor if you should avoid any foods, beverages, or medicines prior to taking the test.

You may need to fast for 4 or more hours before the test.

Make sure you inform your doctor about all medicines and supplements you are taking, including over-the-counter, prescription, and illegal drugs.

Also, avoid the following which may interfere with your urate test results:

  • Alcohol
  • Aspirin and ibuprofen (Motrin IB)
  • High levels of vitamin C
  • Dyes used in X-ray tests
  • Diuretics

Blood Test

Blood analysis for uric acid blood test involved the process of obtaining a blood sample (venepuncture) from a vein, usually from your inner elbow or the back of your hand. 

  1. The area will be first sterilized with an antiseptic.
  2. To allow blood to fill the veins, an elastic band is wrapped around your arm.
  3. A needle is inserted into your vein and blood is collected in an attached vial.
  4. Once the blood has been collected, the band is untied and the needle removed from the vein.
  5. Pressure is applied to the site of the needle entry and a bandage applied if necessary.
  6. Once collected, the blood is sent to a laboratory for analysis.

Interpretation of Test Results

Age, gender, and health history may affect the test result. Results are given in milligrams per deciliter (mg/dL).

Hyperuricemia is characterized by results higher than 6 mg/dL (woman) or 7 mg/dL (man).

Your test results, however, do not mean you have a problem as further investigation is required to determine the cause of the overproduction or decreased elimination of uric acid.

Hyperuricemia typically indicates that your body is making too much uric acid or that your kidneys aren’t removing enough uric acid from your body.

High uric acid levels in your blood can also indicate a variety of conditions, including:

  • diabetes;
  • chemotherapy; 
  • bone marrow disorders;
  • a diet high in purines; 
  • hypoparathyroidism;
  • kidney disorders;
  • kidney stones; 
  • multiple myeloma; or
  • metastasized cancer.

The break-down of purines is affected by several genetic inborn errors.

Metastasized cancer, multiple myeloma, leukemia, and cancer chemotherapy can cause increased production of uric acid while chronic renal disease, acidosis, toxemia of pregnancy, and alcoholism leads to decrease elimination of uric acid.

Foods high in purines are associated with high levels of uric acid. High levels can also be caused by a low-salt diet.

The urate testing isn’t considered a definitive test for gout.

It’s possible to have high uric acid levels without the symptoms of gout (asymptomatic hyperuricemia).

The presence of gout can only be confirmed by testing a person’s joint fluid for monosodium urate.

However, your doctor can make an educated guess based on your urate blood levels and your gout symptoms.

Factors Affecting My Test Results

Some medicines may affect your test results. These include:

  • Aspirin and other medicines that contain salicylate; 
  • Cyclosporine, a medicine sometimes used for autoimmune diseases;
  • Levodopa, a medicine used to treat Parkinson disease; 
  • Some diuretic medicines such as hydrochlorothiazide; and
  • Vitamin B-3 (niacin). 

Your test results may also be affected by:

  • Vigorous exercise 
  • Chemotherapy or radiation therapy for cancer
  • Foods high in purines, including organ meats, mushrooms, some types of fish and seafood, and dried peas and beans  

Any Risks?

Blood draws are routine and very safe. The risks associated with urate testing are the same as those associated with any venepuncture, which are:

  • pain or discomfort at the puncture site; 
  • Bleeding;
  • fainting or light-headedness;
  • an accumulation of blood under your skin, such as hematoma or bruising; or
  • infection at the puncture site. 

What Other Tests Might I Need?

Based on your symptoms and what your doctor’s looking for, you may be advised:

  • to perform more tests for gout, including one where they take fluid from the joint with symptoms; or 
  • to do a urinalysis, a urine test that looks for more signs of kidney stones.

If you don’t encounter gout or kidney stones, your doctor may order more blood or urine tests to look into what might be triggering high uric acid levels.

Conclusion

Gout is a chronic condition with a considerable impact on the lives of patients and their families.

To ensure effective management of gout, gout patients must realize the rationale for performing a blood test for gout.

To stop gout, you need to first bring your uric acid levels down. The strategy for effective gout management is long-term urate-lowering therapy to maintain the urate below 0.36 mmol/L.

To ensure success for this strategy, regular urate testing and adjustment of urate-lowering therapy are required.

The desirable target of 0.36 mmol/L need to be maintained for long-term approach.

However, uric acid blood tests should not be used alone when diagnosing gout as some people with elevated urate levels never develop gout, and some people with low urate levels do encounter gout.

Other tests are needed in addition to the blood test for gout to confirm whether you have gout or not.

References:

1.https://ard.bmj.com/content/79/1/31

2.https://medlineplus.gov/lab-tests/uric-acid-test/

3.https://wwwn.cdc.gov/nchs/data/nhanes/2013-2014/labmethods/BIOPRO_H_MET_URIC_ACID.pdf

4.https://www.healthline.com/health/uric-acid-blood

5.https://www.kidneyfund.org/kidney-disease/chronic-kidney-disease-ckd/complications/gout/tests-for-gout/

6.https://www.mayoclinic.org/diseases-conditions/gout/diagnosis-treatment/drc-20372903

7.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3359272/

8.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3683400/

9.https://www.nzma.org.nz/journal/read-the-journal/all-issues/2010-2019/2015/vol-128-no-1420-21-august-2015/6626

10.https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=uric_acid_blood

11.https://www.webmd.com/arthritis/uric-acid-blood-test#1

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