Figure 1.
Timing of follow-up sputum smear examinations.
Treatment duration and timing of follow-up sputum smear examinations for new and previously-treated cases of tuberculosis, highlighting the timing of the follow-up mid-continuation phase sputum smear examination. The initial two-three month intensive phase (light blue bars) is followed by a follow-up sputum smear examination (pink bars). If the follow-up sputum smear examination is positive, an additional 1-month extended-intensive phase treatment is given (dark blue bar), with additional follow-up sputum smear examination. After the intensive phase (or extended intensive phase), the continuation phase of treatment (grey bars) is immediately begin. After two months of continuation phase (i.e. between months 4 and 6), the mid-continuation phase (mid-CP) follow-up sputum smear examination is done (red bars, circled with dotted line). At the end of the continuation phase, a final follow-up sputum smear examination is done.
Figure 2.
Flow of cases of sputum smear-positive Tuberculosis as per successive sputum smear microscopy results.
Mid-CP follow-up refers to the sputum smear microscopy which is scheduled between the 4th and 6th month of anti-TB treatment, i.e. in the middle of the ‘continuation phase’ (CP) of typical anti-TB treatment. Cases that are found to be smear-positive at 5th month or later are considered as not responding to treatment (‘treatment failure’). Numerals shown in rectangular boxes refer to number of cases with treatment failure who were detected two-three months earlier than at the end of treatment as they were smear-positive in mid-CP follow-up at or beyond 5th month of anti-TB treatment. Numerals shown in clear ovals refer to number of cases with treatment failure that were detected only at the end of treatment because they were either smear-negative in mid CP follow-up, or had a smear-positive mid-CP result before 5th month of anti-TB treatment. Numerals shown in shaded ovals refer to number of cases with treatment failure who missed their mid-CP follow-up scheduled at or beyond 5th month of treatment. These cases could have been detected two-three months earlier had they undergone mid-CP follow-up and were found to be smear-positive.
Table 1.
Impact of various policy options with regard to mid-CP follow-up on the number of cases of tuberculosis treatment failures detected early1 and laboratory workload.