Table 3. Results of external quality assurance for microscopy.
| CHR | INH | DITM | |||||||
| Swaba | FNAb | Total | Swaba | FNAb | Total | Swaba | FNAb | Total | |
| Phase I | |||||||||
| Positivity rate c | 50.0% (3/6) | 36.4% (4/11) | 41.2% (7/17) | N/A | N/A | N/A | 66.7% (4/6) | 36.4% (4/11) | 47.1% (8/17) |
| False negative results d | 16.7% (1/6) | 0% (0/11) | 5.9% (1/17) | N/A | N/A | N/A | N/A | N/A | N/A |
| False positive results e | 0% (0/6) | 0% (0/11) | 0% (0/17) | N/A | N/A | N/A | N/A | N/A | N/A |
| Discordance rate f | 16.7% (1/6) | 0% (0/11) | 5.9% (1/17) | N/A | N/A | N/A | N/A | N/A | N/A |
| Concordance rate for CHR/DITM g | 83.3% (5/6) | 100% (11/11) | 94.1% (16/17) | N/A | N/A | N/A | N/A | N/A | N/A |
| Case confirmation rate h | 31.3% (5/16) | N/A | 37.5% (6/16) | ||||||
| Phase II | |||||||||
| Positivity rate c | 50.0% (12/24) | 45.8% (22/48) | 47.2% (34/72) | 50.0 (12/24) | 47.9% (23/48) | 48.6% (35/72) | 58.3% (14/24) | 54.2% (26/48) | 55.6% (40/72) |
| False negative results d | 8.3% (2/24) | 10.4% (5/48) | 9.7% (7/72) | 8.3% (2/24) | 6.3% (3/48) | 6.9% (5/72) | N/A | N/A | N/A |
| False positive results e | 0% (0/24) | 2.1% (1/48) | 1.4% (1/72) | 0% (0/24) | 0% (0/48) | 0% (0/72) | N/A | N/A | N/A |
| Discordance rate f | 8.3% (2/24) | 12.5% (6/48) | 11.1% (8/72) | 8.3% (2/24) | 6.3% (3/48) | 6.9% (5/72) | N/A | N/A | N/A |
| Concordance rate for CHR/INH g | 100% (24/24) | 91.7% (44/48) | 94.4% (68/72) | N/A | N/A | N/A | N/A | N/A | N/A |
| Concordance rate for CHR/DITM g | 91.7% (22/24) | 87.5% (42/48) | 88.9% (64/72) | N/A | N/A | N/A | N/A | N/A | N/A |
| Concordance rate for INH/DITM g | N/A | N/A | N/A | 91.7% (22/24) | 93.7% (45/48) | 93.1% (67/72) | N/A | N/A | N/A |
| Case confirmation rate h | 43.9% (29/66) | 47.0% (31/66) | 53.0% (35/66) | ||||||
| Concordance rate g for CHR/DITM – Phase I and II | 89.9% (80/89) | N/A | N/A | ||||||
| Case confirmation rate h – Phase I and II | 41.5% (34/82) | N/A | 50.0% (41/82) | ||||||
Table 3 shows results of Ziehl-Neelsen microscopy conducted at CHR and corresponding results of EQA conducted at INH and DITM during the initial (phase I, September 2010 through December 2010) and transitional (phase II, January 2011 through April 2012) phases. N/A, not applicable.
Swab, slides were prepared as direct smears from swab samples.
FNA, slides were prepared as direct smears from fine-needle aspirate samples.
Positivity rate, number of positive samples divided by the total number of samples tested.
Rate of false negative results at CHR and INH, respectively, compared to DITM results.
Rate of false positive results at CHR and INH, respectively, compared to DITM results.
Rate of false negative and false positive results at CHR and INH, respectively, compared to DITM results.
Rate of concordant results between CHR/INH, CHR/DITM and INH/DITM.
Confirmation rate, number of laboratory confirmed BUD patients divided by the total number of suspected BUD cases.