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Table 2 Comparative performance of SSM versus LAM, and the combination of LAM and SSM versus SSM alone using the microbiological reference standard

From: Comparative performance characteristics of the urine lipoarabinomannan strip test and sputum smear microscopy in hospitalized HIV-infected patients with suspected tuberculosis in Harare, Zimbabwe

  SSM versus LAM Combined SSM and LAM versus SSM alone
N = 457 SSM only LAM only p-value SSM only LAM only SSM plus LAM p-value
Sensitivity 54.9 % 61.0 % 0.429 54.9 %* 61.0 % 74.4 %* 0.009
(95 % CI) (43.5–65.9) (49.6-71.6)   (43.5-65.9) (49.6–71.6) (63.6-83.4)  
n + ve/total 45/82 50/82   45/82 50/82 61/825  
Specificity 95.7 % 86.1 % <0.001 95.7 %* 86.1 % 84.8 %* <0.001
(95 % CI) (93.2-97.5) (82.2-89.5)   (93.2-97.5) (82.2-89.5) (80.8-88.3)  
n -ve/total 359/375 323/375   359/375 323/375 318/375  
PPV 73.8 % 49.0 0.007 73.8 %* 49.0 51.7 %* 0.015
(95 % CI) (60.9–84.2) (39.0-59.1)   (60.9-84.2) (39.0–59.1) (42.3-61.0)  
NPV 90.7 % 91.0 0.876 90.7 % 91.0 93.8 % >0.05
(95 % CI) (87.6-93.6) (87.5-93.8)   (87.6–93.6) (87.5-93.8) (90.7-96.1)  
  1. SSM smear microscopy, LAM Urine Lipoarabinomannan strip test, n + ve number positive, n –ve number negative
  2. P-value indicate significant differences between patient groups (marked with * and number to indicate comparison group) * - Significantly Different (p ≤ 0.05)