TABLE 3.
Diagnostic performance of sputum-based Xpert MTB/RIF and urine-based Alere LAM testing in patients with CD4 counts of ≤50 and ≤200 cells/mm3a
| Reference standard | CD4 count (cells/mm3) | Test strategyb | % (95% CI) |
|||
|---|---|---|---|---|---|---|
| Sensitivity | Specificity | PPV | NPV | |||
| Sputum culture positivity | ≤50 | Xpert MTB/RIF only | 81.5 (71.3–89.2) | 94.3 (89.1–97.5) | 89.2 (79.8–95.2) | 89.9 (83.8–94.2) |
| Urine LAM test only | 60.0 (47.1–72.0) | 81.7 (72.9–88.6) | 67.2 (53.7–79.0) | 76.6 (67.6–84.1) | ||
| Sequential or concurrent testing | 89.2 (79.1–95.6) | 79.8 (70.8–87.0) | 73.4 (62.3–82.7) | 92.2 (84.6–96.8) | ||
| ≤200 | Xpert MTB/RIF Only | 80.3 (72.3–86.8) | 94.9 (91.3–97.3) | 89.5 (82.3–94.4) | 90.0 (85.5–92.4) | |
| Urine LAM test only | 44.9 (36.1–54.0) | 88.1 (83.3–92.0) | 67.1 (56.0–76.9) | 74.8 (69.3–79.8) | ||
| Sequential or concurrent testing | 83.5 (75.8–89.5) | 84.7 (79.5–89.1) | 74.6 (66.7–81.6) | 90.5 (85.8–94.0) | ||
| Any microbiological test positivityc | ≤50 | Xpert MTB/RIF only | 71.3 (60.6–80.5) | 77.1 (70.7–82.4) | ||
| Urine LAM test only | 66.7 (55.8–76.4) | 74.3 (68.3–79.6) | ||||
| Sequential or concurrent testing | 92.0 (84.1–96.7) | 92.3 (85.5–96.1) | ||||
| ≤200 | Xpert MTB/RIF only | 69.9 (62.3–76.9) | 80.3 (76.4–83.8) | |||
| Urine LAM test only | 52.2 (44.1–60.0) | 71.9 (68.6–75.1) | ||||
| Sequential or concurrent testing | 87.1 (81.0–91.8) | 90.5 (86.5–93.4) | ||||
Diagnostic performance of sputum-based Xpert MTB/RIF and urine-based Alere LAM in single, sequential, and concurrent testing strategies in HIV-infected hospitalized patients with CD4 counts of ≤50 and ≤200 cells/mm3 using sputum culture or any microbiological test positivity as a reference.
Sequential testing refers to performing Xpert in LAM-negative patients or LAM in Xpert-negative patients; concurrent testing refers to performing both Xpert and LAM concurrently.
Specificity and PPV could not be determined when any microbiological test positivity is used as a reference standard (as this will always equate to 100%).