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Automated counting of nucleated cells in equine synovial fluid without and with hyaluronidase pretreatment
Author(s) -
Ekmann Anita,
Rigdal MarieLouise,
Gröndahl Gittan
Publication year - 2010
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/j.1939-165x.2009.00203.x
Subject(s) - synovial fluid , hemocytometer , cell counting , hyaluronidase , hematology analyzer , pathology , coefficient of variation , medicine , nuclear medicine , biomedical engineering , chromatography , chemistry , cell , osteoarthritis , biochemistry , enzyme , alternative medicine , cell cycle
Background: Microscopy is usually used to obtain manual total and differential cell counts in equine synovial fluid. A faster, more precise method is desirable. Objectives: The objectives were to compare an automated impedance method with a manual method for obtaining total and differential cell counts in equine synovial fluid and to evaluate the effect of pretreatment with hyaluronidase on automated results. Methods: Synovial fluid samples ( n =48) were collected into EDTA and analyzed within 48 hours. Automated total and differential cell counts were evaluated using a Medonic CA620‐VET hematology analyzer before and after pretreatment for 5–30 minutes with hyaluronidase (final concentration 0.01 mg/mL). A hemacytometer count and microscopic evaluation of a direct smear were used as the reference method. Intra‐assay coefficients of variation (CV) were determined. Results: Thirty‐one of 46 untreated samples and 0/46 hyaluronidase‐treated samples were error‐flagged by the analyzer. Correlation between automated (ANCC) and manual (MNCC) nucleated cell counts in untreated samples ( n =15; R 2 =0.93) and pretreated samples ( n =46; R 2 =0.94) was high, and pseudomedian difference was low. Intra‐assay CVs for samples with medium and high cellularity were significantly lower for ANCC (1.5–2.7%) compared with MNCC (6.1–15.7%) ( P <.01). Valid automated differential cell counts were not obtained. Conclusions: Automated total cell counts obtained on the Medonic analyzer correlate well with manual counts in equine synovial fluid; however, pretreatment with hyaluronidase is required to minimize error flags. Automated differential counts are not accurate for synovial fluid.