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. 2021 Feb 18;59(3):e02232-20. doi: 10.1128/JCM.02232-20

TABLE 2.

Tracheal aspirate specimen collection, processing, and Gram staining

Laboratory process No. (%)
Specimen collection and receipt
 Labs that are aware if a tracheal aspirate specimen has been diluted with saline upon receipt in the laboratory (n = 71) 5 (7)
 Labs with rejection criteria for tracheal aspirate specimens based on time from collection to delivery in the microbiology laboratory (n = 72) 32 (44)
 Criteria of laboratories with time rejection criteria (n = 31)
  >2 hours after collection if refrigerated OR >24 hours after collection 24 (75)
  After 30 min to 1 hour of collection 3 (9)
  >4 days after collection 1 (3)
  Same day 1 (3)
  Other 3 (9)
 Labs with rejection criteria for tracheal aspirate specimens based on container type (n = 72) 27 (38)
 Labs performing surveillance tracheal aspirate cultures (n = 73) 4 (5)
 Labs that process tracheal aspirate specimens for culture in-house (n = 73) 61 (84)
Tracheal aspirate Gram staining
 Labs that prepare a tracheal aspirate Gram stain by selecting the most purulent area of the specimen and spreading it on to a slide (n = 61) 60 (98)
 Labs that reject tracheal aspirate specimens for culture based on Gram stain criteria (n = 61) 14 (23)
 Criteria for rejection based on Gram stain (n = 14)
  Rejection based on number of epithelial cells seen 7 (50)
  Rejection based on Q score 1 (7)
  Rejection based on a combination of epithelial cell, PMN, and organism quantities 6 (43)
 Microscope objective used to observe human cells in tracheal aspirate Gram stains (n = 61)
  10× 39 (64)
  40× 6 (10)
  100× 14 (23)
  10× for epithelial cells, 100× for PMNS 2 (3)
 Labs using the 100× microscope objective to view organisms on tracheal aspirate Gram stains 60 (98)
 Labs using minimum Gram stain field review criteria 34 (56)
 Criteria used for minimum field review (n = 34)
  5–15 fields 8 (23)
  20–40 fields 19 (56)
  50–100 fields 4 (12)
  "several" 2 (6)
  1/2 of the slide 1 (3)
 Gram stain quantitative methods (n = 61)
  Quantitatively (e.g., X number of organisms or cells per high power field) 3 (5)
  Semiquantitatively (e.g., rare, few, moderate, heavy) 57 (93)
  No form of quantitation (organisms or cells are listed) 1 (2)
 Labs culturing tracheal aspirate specimens in-house (n = 60) 60 (100)
 Lab plating methods for tracheal aspirate cultures (n = 61)
  Semiquantitative: quadrants are streaked on the plate and growth is reported as either a version of rare, few, moderate, heavy, or 1+, 2+, 3+, 4+ 56 (92)
  Quantitative: colonies are counted and multiplied by a dilution factor 3 (5)
  Other 2 (3)