title: Cytospin preparations are superior to common smears in the detection of monosodium urate crystals in low-cellular synovial fluids.
abstract: In cases of gout with a low synovial fluid (SF) leukocyte count and atypical clinical presentation, such as in intercritical periods, the load of monosodium urate (MSU) crystals is frequently low, and thus, methods to improve the crystal detection may be beneficial. We compared the MSU crystal detection rates between cytospin slides and common smear preparations in low-cellular (<2,000/μl) SF samples of patients with gout. We determined the number of MSU crystals/15 high power fields (HPF) at × 1,000 magnification by polarised microscopy in cytospin preparations and smears in SF samples of 17 patients with MSU-crystal-proven gout and compared the two methods statistically. All of the cytospin slides (100 %) contained MSU crystals and showed a median number of 124 crystals/15 HPF (range 2-3,915), whereas 5 of the 17 smears (29 %) were MSU-crystal-negative, with a median count of 2 crystals/15 HPF (range 0-430/HPF). The difference was statistically highly significant (p < 0.0001). In conclusion, we have shown that the cytospin technique is superior to smears in the detection of MSU crystals in SF with a low SF leukocyte count. In light of our observations, we recommend the use of cytocentrifuges for routine crystal analysis in such cases.
authors.affiliation: Central Laboratory, Hospital of the Brothers of St. John of God, Bergstrasse 27, 8020, Graz, Austria, christoph.robier@bbgraz.at.
authors.forename: Christoph
authors.initials: C
authors.lastname: Robier
authors.forename: Mariana
authors.initials: M
authors.lastname: Stettin
authors.forename: Franz
authors.initials: F
authors.lastname: Quehenberger
authors.forename: Manfred
authors.initials: M
authors.lastname: Neubauer
mesh_terms: D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D002131:Calcium Pyrophosphate / Q000032:analysis; D003460:Crystallization; D005260:Female; D006073:Gout / Q000652:urine*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D013582:Synovial Fluid / Q000737:chemistry*; D013583:Synovial Membrane / Q000378:metabolism; D014527:Uric Acid / Q000032:analysis / Q000737:chemistry*
chemical_list: D014527:Uric Acid; D002097:C-Reactive Protein; D002131:Calcium Pyrophosphate
references.citation: Clin Rheumatol. 2013 Feb;32(2):225-32
references.pmid: 23138881
references.citation: Aust N Z J Med. 1991 Oct;21(5):710-3
references.pmid: 1759919
references.citation: Ann Rheum Dis. 2011 Jun;70(6):1163-4
references.pmid: 20971716
references.citation: Ann Rheum Dis. 1998 Feb;57(2):107-9
references.pmid: 9613340
references.citation: Diagn Cytopathol. 1998 Jul 1;19(1):70-4
references.pmid: 9664189
references.citation: Ann Rheum Dis. 1989 Dec;48(12):983-5
references.pmid: 2559666
references.citation: Rheumatology (Oxford). 2009 May;48 Suppl 2:ii2-ii8
references.pmid: 19447779
references.citation: Ann Rheum Dis. 2002 Jun;61(6):493-8
references.pmid: 12006320
references.citation: Ann Rheum Dis. 2006 Oct;65(10):1301-11
references.pmid: 16707533
references.citation: Acta Cytol. 2012;56(1):68-73
references.pmid: 22236748
references.citation: J Hosp Infect. 1998 Dec;40(4):263-74
references.pmid: 9868617
references.citation: Rheumatol Int. 2014 Jun;34(6):773-6
references.pmid: 23388697
references.citation: Diagn Cytopathol. 2000 Apr;22(4):256-8
references.pmid: 10787150