Quality assurance studies in eight State tuberculosis laboratories in India.
METHODS
Tuberculosis Research Centre, Chennai, India.


OBJECTIVE
To undertake quality assurance studies in sputum smear microscopy at eight State-level laboratories in India using a panel of stained smears.


METHODS
Coded panels of stained smears (100 slides in rounds I-IV and 50 slides in Round V), comprising different grades of positivity, were sent to each centre at 6-monthly intervals. The results obtained were analysed for consistency of positive and negative results and overall agreement, as well as discordance.


RESULTS
Consistency of positives ranged from 38% to 100%, indicating under-reading at some sites. The negative consistency was better, however, with only five of the total of 95 readers in all rounds yielding a consistency of less than 100%. Considering overall agreement, seven of the eight centres showed an agreement of over 90%. Four of the eight centres gave no false-positive result. For the remaining centres the false positivity rate varied from 2% to 7%. A wide variation was also observed in the proportion of false-negatives (3%-52%).


CONCLUSIONS
This study helped in the evaluation of the performance of individual laboratories and in identifying the drawbacks of this system of proficiency testing.
Paramasivan
C N
CN
Tuberculosis Research Centre, Chennai, Tamil Nadu, India. sivamparam@hotmail.com
Venkataraman
P
P
Vasanthan
J S
JS
Rahman
F
F
Narayanan
P R
PR
D002983:Clinical Competence; D019411:Clinical Laboratory Techniques; D003951:Diagnostic Errors; D006078:Government Programs; D006801:Humans; D007194:India; D008853:Microscopy; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D015397:Program Evaluation; D011785:Quality Assurance, Health Care; D015203:Reproducibility of Results; D013183:Sputum / Q000166:cytology / Q000382:microbiology; D013597:Systems Analysis; D014397:Tuberculosis, Pulmonary / Q000382:microbiology* / Q000473:pathology*