title: Concordance between fresh joint fluid analysis by the rheumatologist and joint fluid analysis at the laboratory: Prospective single-center study of 180 samples.
abstract: OBJECTIVE
  To assess the diagnosis usefulness of fresh joint fluid analysis by the rheumatologist.
  
  
  METHODS
  Prospective single-center 1-year study at a university hospital in Rennes, France. A rheumatologist determined whether the freshly collected fluid suggested a mechanical or inflammatory condition and contained monosodium urate (MSU) and/or calcium pyrophosphate (CCP) microcrystals. Agreement between the rheumatologist results and laboratory results was assessed based on the kappa coefficient (κ). We then determined the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of joint fluid analysis by the rheumatologist and by the laboratory, using the final diagnosis based on the full set of clinical, laboratory, and imaging findings as the reference standard.
  
  
  RESULTS
  We included 180 joint fluid samples. The κ values were 0.80 for mechanical or inflammatory fluid, 0.97 for presence of MSU microcrystals, and 0.69 for presence of CCP microcrystals. The rheumatologist findings had 94.2% sensitivity and 84.6% specificity for inflammation; corresponding values were 80.7% and 100% for MSU microcrystals and 66.7% and 93.2% for CCP microcrystals.
  
  
  CONCLUSIONS
  Fresh joint fluid examination by the rheumatologist shows good to excellent agreement with the laboratory analysis for determination of the mechanical or inflammatory nature of the fluid and for detection of MSU and CCP microcrystals.
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France.
authors: Stéfan
authors: S
authors: Pollet
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France. Electronic address: guillaume.coiffier@chu-rennes.fr.
authors: Guillaume
authors: G
authors: Coiffier
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France.
authors: Jean-David
authors: JD
authors: Albert
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France.
authors: Gérard
authors: G
authors: Chales
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France.
authors: Pascal
authors: P
authors: Guggenbuhl
authors: Service de rhumatologie, CHU de Rennes, hôpital Sud, 16, boulevard de Bulgarie, BP90347, 35203 Rennes cedex 2, France.
authors: Aleth
authors: A
authors: Perdriger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002131:Calcium Pyrophosphate / Q000032:analysis; D003460:Crystallization; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis*; D007755:Laboratories, Hospital / Q000592:standards; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012219:Rheumatology / Q000592:standards; D012680:Sensitivity and Specificity; D013582:Synovial Fluid / Q000737:chemistry; D014527:Uric Acid / Q000032:analysis; D055815:Young Adult
chemical_list: D014527:Uric Acid; D002131:Calcium Pyrophosphate
keywords: Chondrocalcinosis; Gout; Joint fluid; Light microscopy; Microcrystals