Besides evaluating symptoms, performing a clinical examination and measuring of blood uric acid levels, the most conclusive test is a joint aspiration. This is a simple procedure where a needle is used to remove a sample of fluid from the affected joint. The presence of uric acid crystals (monosodium urate crystals) confirms the diagnosis of gout. However, the absence of such crystals does not rule out gout. Most people with gout have hyperuricaemia but hyperuricaemia may not be present during an acute attack. Hyperuricaemia alone does not mean that a person has gout.