Ahmad et al. BMC Public Health 2012, 12:132 http://www.biomedcentral.com/1471-2458/12/132 Page 3 of 6 +++/++- (n=35) TB sm+ = 35 Lost n=4 Lost n=2 TB Suspect (n= 724) SMS Sputum (n=502) + - - (n=4) + (n=1) Lost TB sm+ = 1 n=1 Chest X ray (n=2) TNBonsmTB+ ==02 SMS Sputum (n=2) Lost n=5 - (n=1) Chest X ray TNBonsmTB- ==00 Standardized diagnostic pathways Lost n=204 - - - (n=461) Antibiotics (n=133) Clinical Improvement (n=111) Non TB = 111 Lost n=1 + (n=1) TB sm+ = 1 No clinical Improvement (n=17) SMS Sputum (n=9) - (n=7) Chest X ray (n=3) TB sm- = 1 Non TB = 2 Antibiotics* (n=9) Non TB == 54 Lost Chest X ray (n=12) TB sm- = 1 Non TB = 11 Chest X-ray (n=76) TB sm+ = 15 TB sm- = 9 Non TB = 52 SMS(nS=p5u)tum* TB sm+ = 1 Non TB = 3 Lost = 1 Chest X-ray* (n=8) TB sm- = 5 Non TB == 12 Lost Antibiotics* (n=3) Tissue biopsy* (n=1) Non TB = 3 EP TB = 1 SMS Sputum Chest X-ray (n=53) TB sm+ = 11 TB sm- = 5 Non TB = 37 SMS Sputum Antibiotics (n=39) TB sm+ = 3 Non TB = 19 Lost = 17 Chest X-ray Antibiotics** (n=10) Non TB = 10 SMS Sputum Chest X-ray Antibiotics (n=31) TB sm- = 2 Non TB = 29 Chest X-ray Antibiotics (n=2) PCR* (n=1) Clinical Improvement (n=104) Non TB = 2 Non TB = 1 Non TB = 104 Figure 1 Pathway of diagnostic work-up of patients suspected of having TB in lung clinics and health centres. Green boxes represent the standardised national TB diagnostic algorithm and the number of patients whose diagnostic work-ups followed the standardised algorithm. Red arrows and boxes represent diagnostic work-ups that did not follow the standardised algorithm. Black boxes represent patients who were lost during diagnostic work-up. Broken arrows represent subsequent diagnostic examinations not shown in the graph. All patients who completed diagnostic work-up underwent sputum smear examinations at a certain point during their diagnostic work-up. After each sputum examination, or series of sputum examinations, the possible outcomes are indicated by ‘+’ (positive) or ‘-’(negative). TB: tuberculosis; EP TB: extra- pulmonary TB; TB sm+: smear-positive tuberculosis; TB sm-: smear-negative tuberculosis. * Pathway that occurred in health centres only. ** Pathway that occurred in lung clinics only (n = 153) followed the standardised algorithm and com- pleted the diagnostic work-up. Of 461 suspects who first received sputum smear examinations but had negative results, 136 (29.5%) fol- lowed non-standardised pathways (Figure 1) and 22.6% (n = 104) were diagnosed as non-TB because of clinical improvement. Approximately 30% (n = 218) of patients did not follow the national algorithm from the start of TB Suspect n= 724 Lung clinics n=170 (23.5%) Health centres n=554 (76.5%) Lost n=0 (0%) Complete n=170 (100%) n=241Lo(4st3.5%) Complete n=313 (56.5%) Adherence n=0 (0%) Non adherence n=170 (100%) Adherence n=153 (48.9%) Non adherence n=160 (51.1%) TB smear+ : 27 (15.9%) TB smear- : 12 (7.1%) Non TB : 131 (77.0%) TB smear+ : 39 (25.5%) TB smear- : 1 (0.7%) Non TB : 113 (73.8) TB smear+ : 3 (1.9%) TB smear- : 11 (6.9%) Non TB : 146 (91.2%) Figure 2 Adherence to the national TB diagnostic algorithm and outcomes of diagnostic work-ups in lung clinics and health centres. the diagnostic work-up. The diagnostic work-up started with chest radiography, an antibiotic trial, or a combina- tion of these procedures with sputum smear microscopy. Notably, all TB suspects who were not lost to follow up underwent sputum smear microscopy at some point during their diagnostic work-up. Patients were lost at every level of the diagnostic work-up (Figure 1), even at very early stages. The high- est frequency of loss occurred after an initial set of negative sputum results, 44% (n = 204) of the 461 smear-negative patients. Patient loss was similar in males and females but varied slightly among different age groups (Table 1). Patient loss was significantly higher in SHC compared to MHC (OR 2.06, 95% CI 1.41-3.02, P < 0.001). For the TB suspects who completed the diagnostic process, the type of health facility and gender was not associated with TB diagnosis (data not shown); only older age was associated with TB diagnosis (OR 0.75, 95% CI 0.66-0.86, P < 001). No significant differences were found between patients diagnosed with smear-posi- tive TB and smear-negative TB in terms of gender, age group, and type of health facility where they were diag- nosed (data not shown), and only sputum smear as the