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Table 1 Demographics and T-Spot results of all participants

From: High background rates of positive tuberculosis-specific interferon-γ release assays in a low prevalence region of UK: a surveillance study

  Exposed Unexposed
  Staff   Patients   Staff   Patients  
  n=142   n=134   n=22   n=156  
  n % (95% CI) n % (95% CI) n % (95% CI) n % (95% CI)
Age (years), median (range) 34 (18 to 69)   73 (27 to 95)   44 (23 to 60)   71 (25 to 93)  
Male, n (%)† 25 (17)   60 (45)   7 (32)   77 (49)  
Ethnicity, n (%)             
  White Caucasian - -   133 (99)   20 (91)   156 (100)  
  Hispanic - -   1 (0.7)   0 (0)   0 (0)  
  Asian‡ - -   0 (0)   2 (9)   0 (0)  
BCG (history or scar), n (%)             
  Yes 119 (84)   55 (41)   18 (82)   75 (48)  
  No 8 (5.6)   57 (43)   3 (14)   50 (32)  
  Unknown 1 (0.7)   22 (16)   1 (5)   30 (19)  
TSpot result including initial borderline results, n, (%) (95%CI)          
  Positive 14 (9.9) (5.0 to 15) 28 (21) (14 to 27) 2 (9.1) (0 to 21) 13 (8.3) (4.0 to 13)
  Borderline positive (1.4) (0 to 3.3) 3 (2.2) (0 to 4.7) 0 (0) (N/A) 5 (3.2) (0.44 to 6.0)
  Borderline negative (4.2) (0.92 to 7.5) 1 (0.7) (0 to 2.2) 1 (4.5) (0 to 13) 2 (1.3) (0 to 3.0)
  Negative 120 (85) (79 to 90) 102 (76) (68 to 82) 19 (86) (72 to 100) 136 (87) (82 to 92)
TSpot result excluding those borderline results which were not retested, n, (%) (95%CI)        
  Positive 16 (11) (6.1 to 16) 28 (22) (14 to 29) 2 (9.5) (0 to 22) 13 (8.7) (4.2 to 13)
  Negative 126 (89) (84 to 94) 102 (78) (71 to 85) 19 (90) (78 to 100) 136 (91) (87 to 96)
  1. † Percentages are those of those with valid data (e.g. occupation).
  2. ‡ India (1), Philippines (1).
  3. § Borderline results were retested and definitive results reached in every case. 2 (of which one was borderline negative) became positive (conversions), 6 (of which one was borderline negative) became negative (reversions).