From the Guidelines
Gout diagnosis is primarily confirmed through synovial fluid analysis, which is considered the gold-standard diagnostic test 1.
Diagnostic Tests for Gout
- Synovial fluid analysis: This involves aspirating fluid from the affected joint and examining it under a polarizing microscope for the presence of monosodium urate (MSU) crystals, which is the most accurate method for diagnosing gout 1.
- Clinical prediction tools: Several clinical prediction tools have been developed, which can be used in primary care settings, with sensitivities and specificities greater than 80% for diagnosing early-onset gout compared to synovial fluid MSU crystal analysis 1.
- Dual-energy computed tomography (DECT): DECT is a non-invasive imaging test that can detect MSU crystals in the joints, but its usefulness in primary care settings is uncertain due to limited evidence 1.
- Ultrasonography: Ultrasonography can also detect MSU crystals and other signs of gout, but its accuracy and utility are affected by several factors, including operator experience and equipment quality 1.
- Serum urate analysis: While serum urate levels can be elevated in patients with gout, this test is not specific for gout and can be influenced by various factors, such as kidney function and diet 1.
- Plain radiography: Plain radiography can show joint damage and other signs of chronic gout, but it is not useful for diagnosing acute gouty arthritis 1.
The American College of Physicians recommends using synovial fluid analysis when clinical judgment indicates that diagnostic testing is necessary in patients with possible acute gout 1. However, clinical algorithms and other diagnostic tests can be used in primary care settings when synovial fluid analysis is not feasible or available 1.
From the Research
Diagnostic Tests for Gout
The diagnosis of gout can be confirmed through various tests, including:
- Laboratory tests: identification of characteristic MSU crystals in the synovial fluid using polarized light microscopy is considered the gold standard for diagnosis 2, 3, 4, 5
- Radiological features: imaging modalities such as conventional radiography, ultrasonography, conventional CT, Dual-Energy CT, Magnetic Resonance Imaging, nuclear scintigraphy, and positron emission tomography can be used to support the diagnosis 2, 4
- Clinical criteria: evaluation of clinical signs, laboratory results, and imaging results is generally required for diagnosis of gout in cases where MSU crystals have not been detected 3, 5, 6
- Joint aspiration: examining the synovial fluid with a polarized light microscopy can confirm the diagnosis of gout 4
Imaging Modalities
Various imaging modalities can be used to support the diagnosis of gout, including:
- Conventional radiography
- Ultrasonography
- Conventional CT
- Dual-Energy CT
- Magnetic Resonance Imaging
- Nuclear scintigraphy
- Positron emission tomography 2, 4
Laboratory Tests
Laboratory tests play a crucial role in the diagnosis of gout, including: