Table 1 Criteria used to evaluate Gram smears of wound swabs submitted for culture.

From: Wound swab quality grading is dependent on Gram smear screening approach

Current laboratory grading scheme (OM100)a

Q score grading scheme

(QS10 and QS100)b

# of cells per field (100X)

Score

(PMNs and SECs)

# of cells per field (10X or 100X)c,d

Score (PMNs)

Score (SECs)

< 1

Occasional

0

0

0

1–5

Few

1–9

1

− 1

5–10

Moderate

10–24

2

− 2

≥ 10

Many

≥ 25

3

− 3

  1. aOM100 represents the Gram smear grading method used by the laboratory at the time of the study which provides a semi-quantitative assessment of the presence of squamous epithelial cells (SECs) and polymorphonuclear cells (PMNs) under high power (100X objective).
  2. bThe Q score was determined by assessing the number of PMNs and SECs per field under (ii) low power (10X objective) (QS10) and (iii) high power (100X objective) (QS100).
  3. cThe same number of cells per field were used for scoring under both QS10 and QS100.
  4. dThe number of cells per field (100X) from the OM100 scheme was used for the QS100 Q score criteria applied to retrospectively collected wound swabs.
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