Table 3. Summary of rechecking and mixed EQA studies.
|
Country / (Reference) |
Methodology | Results |
|---|---|---|
| India (41) | 41,978 TB slides from 12 microscopy centres rechecked by supervisors and national level | False negatives 2–7% by centres; 0–3% by supervisors; re-staining and blinded rereading reduced false positives from 27% to 7% |
| India (43) | 40,506 TB slides from 183 microscopy centres rechecked by district supervisors | 446 errors (2.2%) |
| India (44, 45) | 1547 TB slides from 7 microscopy centres rechecked by district supervisors; 726 TB slides from 5 microscopy centres rechecked at reference level | 70 errors by district supervisors; 2 errors by reference laboratory reader |
| Ethiopia (46) | 39,725 TB slides from 201 laboratories rechecked at 26 EQA centres | 68 false positives in 41 (20.4%) laboratories; 67 false negatives in 29 (14.4%) laboratories |
| Ethiopia (47) | 2209 TB slides rechecked at regional level; discordant slides rechecked at national level | 96.8% overall agreement; 3.2% false positives; 74% agreement between regional and national readers on 95 discordant slides |
| Malawi (48) | 208 TB smears from 1 hospital/32 health centres rechecked at district hospital | Concordance 98.1% for positive smears; 98.2% for negative smears |
| Ethiopia (49) | 37 public-private mix laboratories: 1123 TB smears rechecked at regional laboratory PT of 370 TB panel smears |
99.4% agreement Overall agreement 96%; errors reading unstained and ready-stained smears 62% vs. 38% |
| Ethiopia (50) | 8 health institution laboratories: 578 TB smears rechecked at university laboratory PT of 10 TB panel smears |
94.5% agreement; 3 (3.75%) major errors (high false positives) Overall error 17 (25.25%); 14 (17.5%) minor errors; 3 (3.75%) major errors (high false positives) |
| Burundi (51) | 1014 TB slides from 72 microscopy centres rechecked at reference level | 31.2%/6.9% false positives; 1.2%/4.1% false negatives before/after re-staining. |
| Rwanda (53) | 20 positive, 20 negative malaria slides from 3 laboratories rechecked at reference level | 96.67% agreement |
| Pakistan (54) | On-site rechecking of 1170 malaria slides in 4 districts by district supervisors | 0.5–1% discordance |
| Kenya (55) | 4514 malaria slides rechecked from 17 health centres by study microscopist | Average sensitivity 96%, specificity 88% |
| Nigeria (56) | TB slides from 5 centres; malaria slides from 2 centres rechecked at state level | From baseline to final assessment: Concordance for TB microscopy increased from 81% to 91.0% Concordance for malaria microscopy increased from 69.2% to 83.3% at 1 laboratory; decreased from 100% to 83.3% in second laboratory. |
| Nepal (57) | DBS from 5 centres retested using repeat HIV RDT and ELISA at national level | RDT results 100% concordant ELISA: 32 samples (91.4%) concordant; 3 samples (8.6%) discordant; sensitivity 88.9%; specificity 94.0% |
| Ethiopia (58) | 64 TB slides, 64 malaria slides, 64 HIV blood samples from 4 health centres rechecked at district level | Agreement of 98.4% (63/64), 92.2% (59/64) and 95.3% (61/64) for TB microscopy, malaria microscopy and HIV rapid testing |
| TB – tuberculosis; EQA – external quality assessment; PT – proficiency testing; DBS – dried blood spots; RDT – rapid diagnostic test; ELISA – enzyme-linked immunosorbent assay. | ||