[□] QUALITY CONTROL ON SPUTUM SMEAR EXAMINATION
13) Key operations of microscopy services
The smear microscopy is a core of DOTS strategy because it is entirely dependent on the result of sputum smear examination. To provide an accurate and reliable microscopy services, several issues, namely; 1)laboratory network, 2)standard manual, 3)fulltime working staff, 4)training, 5) regular supply of reagents and materials, 6)recording and reporting system, and 7) quality control and supervision system should be considered.
The quality of smear examination is not affected only by the quality of staining techniques but also by the organization and management of resources.
14) Pictures of QC Center
To ensure high quality of smear microscopy services, regular checks or quality control on smear examination is one of the most efficient activities.
Quality control can be operated not only by cross-checking of smear slides but also by assessment of quality of smear preparation.
15) QC System flow chart in Cebu City
Quality control of smear examination is introduced through the experience in the Philippines. Flowchart of quality control system is shown here and the system is described briefly.
All smear slides examined at the peripheral microscopy centers are sent to QC center.
The slides are selected randomly by the provincial NTP coordinator and these selected slides are given to the assessor for blind cross-checking and evaluation of smear preparation. The assessment is made based on the results of false (+)/(-), over all agreement of grade. Since a good smear is critical for accurate diagnosis, proportion of good quality of smear preparation is also assessed in terms of sputum quality, staining, smear cleanness, smear area size, smear thickness and evenness.
The feed-back and follow-up action of these results are given to the peripheral microscopy center by supervisors during supervisory visit.
16) The results of QC
The activities of TB smear examination in Cebu City were analyzed with the results of quality control reported from January 1997 to December 1998 in the 5 peripheral laboratories. Total smear slides checked for quality control in 1997 and 1998 were 4775 and 4249 respectively.
Comparing the results from first quarter of 1997 and the last quarter of 1998, the improvement was observed in all assessment points of smear preparation.
In particular, remarkable improvement was observed in staining from 56.2% to 96.0% and in smear thickness from 48% to 91.2%, which was almost doubled in each assessment point of smear preparation.
The marked improvement was noted within 6 months after quality control started. It is suggested that at least 6 months are required and frequent supervisory visit should be made to strengthen the smear preparation.
