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Table 4 Performance of culture in relation to smear microscopy (2010–2012)

From: Feasibility of establishing a biosafety level 3 tuberculosis culture laboratory of acceptable quality standards in a resource-limited setting: an experience from Uganda

Culture method Performance indicator 2010 N (%) 2011 N (%) 2012 N (%)
LJ culture Total (n) 3,818 5,186 1,486
  Culture positive (MTBc) 69 (1.8) 683 (13.2) 447 (30.1)
  Culture negative 3,749 (98.2) 4,503 (86.8) 1,039 (69.9)
  Culture contaminated 70 (1.8) 287 (5.5) 48 (3.2)
  Smear negative among culture positive 19 (27.54) 255 (37.3) 172 (38.5)
  Smear positive among culture positive 46 (66.7) 377 (55.2) 264 (59.1)
  Smear positive among culture contaminated 3 (4.3) 54 (18.8) 14 (29.2)
  Smear positive among culture negative 21 (0.6) 66 (1.5) 72 (6.9)
MGIT culture Total (n) 3,818 5,056 1,226
  Culture positive M. tuberculosis (MTBc) 107(2.8) 777 (15.4) 352 (28.7)
  Culture negative 3,285 (86.0) 2,705 (53.5) 682 (55.6)
  Culture positive with MOTT 112 (2.9) 253 (5.0) 55 (4.5)
  Culture contaminated 314 (8.2) 1,321 (26.1) 137 (11.2)
  MOTT among smear positive 2 (2.8) 33 (6.6) 14 (6.6)
  Smear negative among culture positive (MTBc) 56 (52.3) 575 (74.0) 211 (60.0)
  Smear positive among culture positive (MTBc) 62 (57.9) 452 (58.2) 195 (55.4)
  Smear positive among culture contaminated 0 (0.0) 23 (1.7) 5 (3.6)
  Smear positive among culture negative 8 (0.2) 23 (0.8) 12 (1.7)
  1. Mycobacterial identifications on LJ were done basing on morphological features and Ziehl-Neelsen microscopy were done on doubtful colonies [15].
  2. LJ, Lowenstein-Jensen; MGIT, Mycobacterial growth indicator tube; MOTT, Mycobacterium other than tuberculosis; MTBc, Mycobacterium tuberculosis complex.