From the Guidelines
Uric acid and urate are essentially the same substance in different forms, with uric acid being the protonated form and urate being the ionized form that predominates in the bloodstream. In the context of gout management, it is crucial to understand the distinction between uric acid and urate, as it affects the formation of urate crystals that deposit in joints and tissues, causing gout and other conditions 1. The terms uric acid and urate are often used interchangeably in clinical practice, particularly when discussing blood tests or treatment for conditions like gout, kidney stones, or hyperuricemia, as they're measuring the same substance in different forms. Key points to consider include:
- Uric acid is the protonated form that exists in acidic environments (pH below 5.8)
- Urate is the ionized form (specifically urate anion) that predominates in the bloodstream where pH is around 7.4
- About 98% of uric acid circulates as urate in the human body
- Urate is more soluble than uric acid, which explains why gout attacks often occur in more acidic environments like the big toe joint
- Blood levels of uric acid/urate rising above 6.8 mg/dL (the saturation point) can lead to the formation of urate crystals that deposit in joints and tissues, causing gout and other conditions 1. In clinical practice, understanding the relationship between uric acid and urate is essential for effective management of gout and other related conditions, and healthcare providers should be aware of the interchangeable use of these terms when discussing treatment options with patients.
From the Research
Definition and Relationship
- Uric acid and urate are often used interchangeably, but they have a subtle difference: uric acid refers to the compound itself, while urate refers to the ion form of uric acid 2, 3, 4.
- In the context of gout and hyperuricemia, the terms uric acid and urate are often used to describe the same condition, where excess uric acid leads to the formation of monosodium urate crystals in tissues 2, 3, 4.
Clinical Context
- Hyperuricemia, or elevated serum urate levels, is a key factor in the development of gout, and reducing serum urate levels is a primary goal of treatment 2, 3, 4, 5.
- Urate-lowering therapies, such as allopurinol and febuxostat, aim to reduce serum urate levels and prevent the formation of urate crystals 2, 3, 4, 5.