title: Effect of temperature and storage time on cellular analysis of fresh pleural fluid samples.
abstract: OBJECTIVE
  Despite the methodological variability in preparation techniques for pleural fluid cytology, it is fundamental that the cells should be preserved, permitting adequate morphological classification. We evaluated numerical and morphological changes in pleural fluid specimens processed after storage at room temperature or under refrigeration.
  
  
  METHODS
  Aliquots of pleural fluid from 30 patients, collected in ethylenediaminetetraacetic acid-coated tubes and maintained at room temperature (21 °C) or refrigeration (4 °C) were evaluated after 2 and 6 hours and 1, 2, 3, 4, 7 and 14 days. Evaluation of cytomorphology and global and percentage counts of leucocytes, macrophages and mesothelial cells were included.
  
  
  RESULTS
  The samples had quantitative cellular variations from day 3 or 4 onwards, depending on the storage conditions. Morphological alterations occurred earlier in samples maintained at room temperature (day 2) than in those under refrigeration (day 4).
  
  
  CONCLUSIONS
  This study confirms that storage time and temperature are potential pre-analytical causes of error in pleural fluid cytology.
authors.affiliation: Pleural Laboratory - Pulmonary Division, Heart Institute (InCor), Clinical Laboratory and LIM 03 - Hospital das Clínicas, University of Sao Paulo Medical School, Sao Paulo, Brazil. l.antonangelo@uol.com.br
authors.forename: L
authors.initials: L
authors.lastname: Antonangelo
authors.forename: F S
authors.initials: FS
authors.lastname: Vargas
authors.forename: M M P
authors.initials: MM
authors.lastname: Acencio
authors.forename: A P
authors.initials: AP
authors.lastname: Corá
authors.forename: L R
authors.initials: LR
authors.lastname: Teixeira
authors.forename: E H
authors.initials: EH
authors.lastname: Genofre
authors.forename: R K B
authors.initials: RK
authors.lastname: Sales
mesh_terms: D001826:Body Fluids / Q000166:cytology*; D002467:Cell Nucleus / Q000378:metabolism; D048430:Cell Shape; D006801:Humans; D010994:Pleura / Q000473:pathology*; D011309:Preservation, Biological; D013194:Staining and Labeling; D013696:Temperature; D013997:Time Factors