Calcium pyrophosphate and monosodium urate crystals in synovial fluid as a cause of pseudoeosinophilia

Author(s):  
Christoph Robier ◽  
Manfred Neubauer ◽  
Franz Quehenberger ◽  
Mariana Stettin ◽  
Franz Rainer

AbstractSynovial fluid (SF) leukocytes can be counted microscopically in a Neubauer chamber or by automated procedures using haematology analysers. Knowledge of laboratory artefacts is crucial for the correct interpretation of results obtained using automated methods. SF pseudoeosinophilia has recently been described as a new artefact in patients with crystal-related arthropathies. We investigated whether pseudoeosinophilia of SF is restricted to crystal-related disorders, or if it may also occur in other arthropathies.We compared the percentages of eosinophils in 120 crystal containing SF samples with 185 crystal-free specimens using the Wilcoxon test. Crystal positive samples, determined by polarised microscopy, contained at least two monosodium urate or calcium pyrophosphate crystals per 10 high power fields (630× magnification). True SF eosinophilia was ruled out by microscopic examination of stained slides.Crystal positive samples had significantly higher percentages of eosinophils than the controls (p<0.0001). No significant differences between the two crystal types were found (p=0.693). Thus, pseudoeosinophilia was significantly correlated with the presence of crystals, and none of the distinct crystal types was more likely to be associated with pseudoeosinophilia.In this study, SF pseudoeosinophilia was confirmed as a crystal-related laboratory artefact which has to be considered in the interpretation of automated SF leukocyte differential counts.

2013 ◽  
Vol 80 (3) ◽  
pp. 287-290 ◽  
Author(s):  
Francesca Oliviero ◽  
Anna Scanu ◽  
Paola Galozzi ◽  
Alessandra Gava ◽  
Paola Frallonardo ◽  
...  

Author(s):  
Christoph Robier ◽  
Franz Quehenberger ◽  
Manfred Neubauer ◽  
Mariana Stettin ◽  
Franz Rainer

AbstractAutomated leukocyte differential counts of synovial fluid (SF) can be influenced by laboratory artefacts. Pseudoeosinophilia of SF has recently been first described in association with monosodium urate and calcium pyrophosphate crystals. This study compared automated measurements of the percentages of SF leukocyte fractions by two haematology analysers in order to elucidate the underlying mechanism of pseudoeosinophilia.The percentages of the leukocyte fractions of 17 crystal-containing and 28 crystal-free specimens were compared using the Wilcoxon test. Measurements were performed using the Cell-Dyn 3200 and the ADVIA 2120i, which are based on different techniques.The percentages of eosinophils of the crystal-positive samples determined by the Cell-Dyn 3200 were significantly higher than those assessed by the ADVIA (p<0.0001), whereas the percentages of eosinophils of the controls did not differ significantly between the two devices (p=0.95). The Cell-Dyn 3200 clearly showed the phenomenon of crystal-associated pseudoeosinophilia (p<0.0001), which did not occur in the ADVIA measurements (p=0.28). The percentage of neutrophils was to a lower degree elevated in the crystal group (p=0.015).It was confirmed that SF crystals interfere with the typical light scattering fractions of leukocyte granules and may thus lead to spuriously elevated percentages of eosinophils and neutrophils in SF specimens.


2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Elin Svensson ◽  
Ylva Aurell ◽  
Lennart T. H. Jacobsson ◽  
Anton Landgren ◽  
Valgerdur Sigurdardottir ◽  
...  

Abstract Background A definite diagnosis of gout requires demonstration of monosodium urate crystals in synovial fluid or in tophi, which in clinical practice today seldom is done. Dual energy CT (DECT) has repeatedly been shown to be able to detect monosodium urate crystals in tissues, hence being an alternative method to synovial fluid microscopy. The vast majority of these studies were performed with CT scanners with two X-ray tubes. In the present study we aim to investigate if and at what locations DECT with rapid kilovoltage-switching source with gemstone scintillator detector (GSI) can identify MSU crystals in patients with clinically diagnosed gout. We also performed a reliability study between two independent readings. Methods Patients with new or established gout who had been examined with DECT GSI scanning of the feet at Sahlgrenska University Hospital, Mölndal between 2015 and 2018 were identified. Their medical records were sought for gout disease characteristics using a structured protocol. Urate deposits in MTP1, MTP 2–5, ankle/midfoot joints and tendons were scored semiquantatively in both feet and presence of artifacts in nail and skin as well as beam hardening and noise were recorded. Two radiologists performed two combined readings and scoring of the images, thus consensus was reached over the scoring at each occasion (Espeland et al., BMC Med Imaging. 2013;13:4). The two readings were compared with kappa statistics. Results DECT GSI could identify urate deposits in the feet of all 55 participants with gout. Deposits were identified in the MTP-joints of all subjects but were also present in ankle/midfoot joints and tendons in 96 and 75% respectively. Deposition of urate was predicted by longer disease duration (Spearman’s Rho 0.64, p < .0001) and presence of tophi (p = 0.0005). Artifacts were common and mostly found in the nails (73%), a minority displayed skin artifacts (31%) while beam hardening and noise was rare. The agreement between the two readings was good (Κ = 0.66, 95% CI = 0.61–0.71). Conclusion The validity of DECT GSI in gout is supported by the identification of urate in all patients with clinical gout and the good correlations with clinical characteristics. The occurrence of artifacts was relatively low with expected locations.


2016 ◽  
Vol 75 (Suppl 2) ◽  
pp. 382.1-382 ◽  
Author(s):  
P. Montagna ◽  
R. Brizzolara ◽  
C. Ferrone ◽  
S. Soldano ◽  
M. Cutolo ◽  
...  

2015 ◽  
Vol 82 (6) ◽  
pp. 470-471 ◽  
Author(s):  
Laura B.E. Kienhorst ◽  
Hein J.E.M. Janssens ◽  
Roelant S. Eijgelaar ◽  
Tim R.D.J. Radstake ◽  
Piet L.C.M. van Riel ◽  
...  

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