From the Guidelines
Serum uric acid (SUA) is not typically elevated in cases of general muscle or bone pain, unless gout is suspected, as indicated by the 2017 EULAR evidence-based recommendations for the management of gout 1. When evaluating muscle or bone pain, other tests such as CK, ESR, or CRP for muscle pain, and calcium levels, vitamin D, alkaline phosphatase, or imaging studies for bone pain, are more relevant.
- Serum uric acid testing is primarily used to diagnose gout and kidney stones, not general muscle or bone pain.
- Elevated uric acid levels can cause gout, which presents as severe joint pain, but this is specific to crystalline arthropathy.
- The normal range for serum uric acid is typically 3.5-7.2 mg/dL for men and 2.6-6.0 mg/dL for women, with levels above these potentially indicating hyperuricemia, as discussed in the context of gout management 1.
- If gout is suspected, the definitive diagnosis requires joint fluid analysis to identify urate crystals, not just serum uric acid levels, highlighting the importance of clinical context in interpreting SUA levels 1.
From the Research
Serum Uric Acid and Pain
- Serum uric acid (SUA) levels are associated with various types of pain, including gouty arthritis and non-gouty widespread pain 2.
- Elevated SUA levels are a precursor to gout, which can cause arthritis, soft tissue masses, nephrolithiasis, and urate nephropathy 3.
- Gout is characterized by the deposition of monosodium urate crystals in joints and soft tissues, leading to pain, erythema, and swelling 4, 3.
Relationship between SUA and Pain
- Studies have shown that increased SUA levels are associated with a higher risk of gout flares 5.
- The level of SUA is increased among individuals with widespread pain (>5 locations) independent of underlying diagnoses compared to those with fewer pain sites 2.
- Serum creatinine, body mass index (BMI), the number of pain locations, and sleep disturbances independently contribute to the SUA level and explain 43% of the variation in SUA 2.