31st January 2024

Joint fluid aspiration

Request MC&S Turbid fluid should always be sent for MC&S, and aspirate should be viewed under plain polarised light:

Image Source: Wikimedia Commons (2008). Gout-monosodium-urate crystals in joint fluid (2), Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Gout_-_monosodium_urate_crystals_in_joint_fluid_(2).jpg (Accessed: 30 April 2022).

Image Source: Wikimedia Commons (2020). Birefringence microscopy of pseudogou, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Birefringence_microscopy_of_pseudogout.jpg (Accessed: 30 April 2022).

Prior to joint aspiration, ensure the patient is not on any anticoagulant and has no history of clotting or bleeding disorders. If there is doubt, wait for formal clotting factors and full blood count results to come back before proceeding. 

Bacteraemia is also a relative contraindication- however, if the source is thought to be due to a septic joint, then it should be performed preferably by an orthopaedic doctor.

Severe overlying infection, such as cellulitis over the swollen joint, is a contraindication to joint aspiration as this may introduce infection into a sterile joint.