Affiliation:
1. Department of Rheumatic Diseases, Tokyo Metropolitan Tama Medical Center , Tokyo, Japan
Abstract
ABSTRACT
Objective
To validate the gout analyzer as a clinical method of synovial fluid crystal analysis.
Methods
Thirty knee synovial fluid samples with suspected calcium pyrophosphate (CPP) crystals were analyzed. Within 48 hours after collection, each non-centrifuged sample was examined blindly and independently by one or more rheumatologists in the following order: 1) with an optical microscope under ordinary light, 2) with the same microscope under compensated polarization provided by a gout analyzer, and 3) with a fully equipped compensated polarized microscope with a rotating stage as the gold standard. As a reference, laboratory technicians analyzed fresh, centrifuged synovial fluid using a gout analyzer.
Results
Of the 30 samples analyzed, CPP and monosodium urate (MSU) crystals were detected in 11 and four, non-centrifuged samples, respectively, using a fully equipped compensated polarized microscope. The rheumatologists’ detection rate of crystals in the non-centrifuged synovial fluid under ordinary light and with a gout analyzer was 73.3% and 80%, respectively. The laboratory technicians’ detection rate in fresh centrifuged synovial fluid using a gout analyzer was 100%.
Conclusion
A gout analyzer may be used to diagnose gout and calcium pyrophosphate deposition disease definitively if a fully equipped compensated polarized microscope is unavailable.
Publisher
Oxford University Press (OUP)