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3. Manpower and Training
 

The field staff deployed for the survey comprised of contractual field workers specially recruited for the survey, local health workers from the respective districts, and experienced team leaders from the epidemiology sections of NTI and TRC. In each zone, two teams each consisting of 8-9 contractual field staff were recruited for the survey in north, south and west zones. Five teams were subjected to exhaustive training for eight weeks at TRC. One team was trained at NTI. The contractual field staff for east zone was recruited from among those who had worked in the other zones.

The supervision of the fieldwork in north, west and east zones was undertaken on a constant basis by highly experienced personnel from NTI. The fieldwork in south zone was supervised by TRC. The supervisors constantly monitored the conduct of the fieldwork on a day to day basis to ensure strict adherence to work instructions and maintain high standards. The chief investigator and co-investigators of the study also made periodical supervisory visits to the field areas. The supervision of the fieldwork was also supported by a professor and an associate professor from MGIMS, Wardha in the west zone and by two senior health staff from New Delhi TB Centre in the north zone.

TRAINING

All the six teams were imparted training in a uniform manner, by a team of highly skilled and vastly experienced standardized tuberculin testers and readers adept in the nuances of tuberculin survey. A lot of emphasis was laid on imparting quality training to the recruits in order to inculcate high levels of work ethics and culture. The recruits were trained in various facets of fieldwork viz., preparing sketches of the cluster-layout, registration of children, identification of BCG scar, tuberculin testing and reading, eliciting public co-operation and record maintenance. The duration of the training was about 40 working days and was conducted in five phases.

The first phase of training was for a duration of five working days. During this phase all the trainees were trained in house to house registration of study children, construction of maps, and communication skills to motivate and mobilize community participation. Based on their performance, two trainees were subsequently imparted comprehensive training in planning, eliciting community participation, registration and preparing sketches of the cluster-layout.

In the second phase of training, which was also for a duration of five days, the techniques of tuberculin testing and reading were demonstrated. Trainee testers and readers were identified based on their aptitude for the respective task. Depending upon the size of the batch, two or three trainees were trained as tuberculin testers and an equal number as tuberculin readers. The testers were also trained in the identification of BCG scar.

The third phase of training required 20 working days in which each trainee tester had to test about 60 individuals everyday. The tuberculin testing was done on the volar aspect of the left forearm. All these tests were read by each of the trainee readers during this period. The readers were also trained in the measurement of tuberculin reactions and in the recognition of unpleasant reactions. The importance and the method of maintenance of study records were also taught in this phase.

The fourth phase of the training lasted for five working days and was similar to the third phase but was more intensive.

In the fifth phase of five working days (assessment phase), the trainee testers and readers were assessed as given below :

The trainers closely observed the testers while performing the tests. Each test was recorded as 'satisfactory' if it raised a flat pale wheal with clearly visible pits and well demarcated borders. It was labeled 'unsatisfactory' in case of leakage or subcutaneous injection. The assessment of the testers was done by recording the proportion of unsatisfactory tests. This proportion was found to vary from 1.6% to 4.3% between the different teams (table 3.1).

For assessment of trainee readers, the reaction sizes were read independently by the trainee readers and the standard reader. The trainee readers were also required to measure the reaction sizes twice in a sample (about 10%) of children. The second reading was carried out after a lapse of time as this data was used to evaluate intra-observer consistency. The evaluation of reading was done through the analysis as under:

 

  
  1. Comparing the reaction sizes recorded by the trainee readers and the standard reader in terms of correlation co-efficient, percent agreement and Mean Difference.

  
 

2. Comparing the reaction sizes recorded from the same set of children by various readers in
the individual teams.

  
 

3. Intra-observer consistency.

  
 
A high level of agreement was found between the trainee readers and the standard readers, in respect of all trainees (table 3.2). A similar level of agreement was also found between the reaction sizes as recorded by different trainee readers. The readers were also found to be consistent as revealed by double-reading of the same children (table 3.3).

  
  In view of the above, all the testers and readers trained were found eligible to be employed as such for tuberculin testing and reading for the main study.

  
 
Table 3.1 : Performance of testers in assessment phase
  
 


 
 
Table 3.2 : Assessment of trainee reader vs standard reader

  
 


 
 
Table 3.3 : Intra-observer consistency