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Detection of crystals in synovial fluids by light microscopy: sensitivity and reliability.
Ann Rheum Dis. 1989 Sep; 48(9):737-42.AR

Abstract

Polarised light microscopy of synovial fluid is an established diagnostic technique widely regarded as reliable for the detection of crystals. The threshold concentration of crystals which can be detected has been investigated and the sensitivity and specificity of six observers compared. Various concentrations of laboratory manufactured crystals of monosodium urate monohydrate (MSUM), calcium pyrophosphate dihydrate (CPPD), and basic calcium phosphates (BCP) were added to the synovial fluid. The threshold for reliable identification of MSUM and CPPD was in the range of 10-100 micrograms/ml. False positives were frequent. The mean sensitivity of the six observers for MSUM was 69% and for CPPD was 82%. The mean specificity for MSUM was 97% and for CPPD was 78%. There was much discrepancy in the results of the slides stained with alizarin red S. Thus the value of alizarin red S as a screening test for BCP is questioned. In view of the variable sensitivity and specificity of different observers for MSUM and CPPD and the concentration threshold for reliable crystal identification, greater caution in the interpretation of synovial fluid analysis is advised, and recommendations for increased quality control are supported.

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Authors+Show Affiliations

Gordon C
University Department of Medicine, Bristol Royal Infirmary.
Swan A
No affiliation info available
Dieppe P
No affiliation info available

MeSH

AnthraquinonesCalcium PhosphatesCalcium PyrophosphateCrystallizationFalse Positive ReactionsHumansMicroscopy, PolarizationSensitivity and SpecificityStaining and LabelingSynovial Fluid

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

2478085

Citation

Gordon, C, et al. "Detection of Crystals in Synovial Fluids By Light Microscopy: Sensitivity and Reliability." Annals of the Rheumatic Diseases, vol. 48, no. 9, 1989, pp. 737-42.
Gordon C, Swan A, Dieppe P. Detection of crystals in synovial fluids by light microscopy: sensitivity and reliability. Ann Rheum Dis. 1989;48(9):737-42.
Gordon, C., Swan, A., & Dieppe, P. (1989). Detection of crystals in synovial fluids by light microscopy: sensitivity and reliability. Annals of the Rheumatic Diseases, 48(9), 737-42.
Gordon C, Swan A, Dieppe P. Detection of Crystals in Synovial Fluids By Light Microscopy: Sensitivity and Reliability. Ann Rheum Dis. 1989;48(9):737-42. PubMed PMID: 2478085.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Detection of crystals in synovial fluids by light microscopy: sensitivity and reliability. AU - Gordon,C, AU - Swan,A, AU - Dieppe,P, PY - 1989/9/1/pubmed PY - 1989/9/1/medline PY - 1989/9/1/entrez SP - 737 EP - 42 JF - Annals of the rheumatic diseases JO - Ann Rheum Dis VL - 48 IS - 9 N2 - Polarised light microscopy of synovial fluid is an established diagnostic technique widely regarded as reliable for the detection of crystals. The threshold concentration of crystals which can be detected has been investigated and the sensitivity and specificity of six observers compared. Various concentrations of laboratory manufactured crystals of monosodium urate monohydrate (MSUM), calcium pyrophosphate dihydrate (CPPD), and basic calcium phosphates (BCP) were added to the synovial fluid. The threshold for reliable identification of MSUM and CPPD was in the range of 10-100 micrograms/ml. False positives were frequent. The mean sensitivity of the six observers for MSUM was 69% and for CPPD was 82%. The mean specificity for MSUM was 97% and for CPPD was 78%. There was much discrepancy in the results of the slides stained with alizarin red S. Thus the value of alizarin red S as a screening test for BCP is questioned. In view of the variable sensitivity and specificity of different observers for MSUM and CPPD and the concentration threshold for reliable crystal identification, greater caution in the interpretation of synovial fluid analysis is advised, and recommendations for increased quality control are supported. SN - 0003-4967 UR - https://www.unboundmedicine.com/medline/citation/2478085/Detection_of_crystals_in_synovial_fluids_by_light_microscopy:_sensitivity_and_reliability_ DB - PRIME DP - Unbound Medicine ER -