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Precautions are taken so that bacteria are not introduced into the joint.
Normal joint fluid is viscous and appears clear to light yellow.
Henadzi Pechan / Getty Images
Cloudy joint fluid is abnormal and suggestive ofinflammationor infection.
Bloody joint fluid is also abnormal and may be sparked by trauma to the joint.
Microscopic Examination
Joint fluid is examined under a microscope and blood cell counts are done.
Normal joint fluid has none or few blood cells.
Large numbers of red blood cells indicate bleeding in the joint.
Large numbers of white blood cells can occur with infection,inflammatory arthritis,gout, orpseudogout.
A culture can identify the source of a bacterial infection.
Crystals seen under a microscope are an abnormal finding.Uric acid crystalsare indicative of gout whileCPPD crystalsoccur with pseudogout.
National Library of Medicine: MedlinePlus.Synovial fluid analysis.
Johns Hopkins Medicine.Joint aspiration.
American College of Rheumatology.Joint injections.
American Academy of Family Physicians.Gout: an update.
2020;72(4):557-564. doi:10.1002/art.41141
