Gout laboratory findings
|
Gout Microchapters |
|
Diagnosis |
|---|
|
Treatment |
|
Case Studies |
|
Gout laboratory findings On the Web |
|
American Roentgen Ray Society Images of Gout laboratory findings |
|
Risk calculators and risk factors for Gout laboratory findings |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Laboratory tests
Hyperuricemia is a common feature; however, urate levels are not always raised.[1] Hyperuricemia is defined as a plasma urate (uric acid) level greater than 420 μmol/L (7.0 mg/dL) in males (or 380 μmol/L in females); however, a high uric acid level does not necessarily mean a person will develop gout. Urate is within the normal range in up to two-thirds of cases.[2] If gout is suspected, the serum urate test should be repeated once the attack has subsided. Other blood tests commonly performed are full blood count, electrolytes, renal function and erythrocyte sedimentation rate (ESR). This helps to exclude other causes of arthritis, most notably septic arthritis.
A definitive diagnosis of gout is from light microscopy of fluid aspirated from the joint (this test may be difficult to perform) to demonstrate intracellular monosodium urate crystals in synovial fluid polymorphonuclear leukocytes. The urate crystal is identified by strong negative bi-refringence under polarised microscopy and its needle-like morphology. A trained observer does better in distinguishing them from other crystals.
References
- ↑ Sturrock R (2000). "Gout. Easy to misdiagnose". BMJ. 320 (7228): 132&ndash, 3. PMID 10634714.
- ↑ Siva C, Velazquez C, Mody A, Brasington R (2003). "Diagnosing acute monoarthritis in adults: a practical approach for the family physician". Am Fam Pghysician. 68 (1): 83&ndash, 90. PMID 12887114.