Proficiency to read sputum AFB smears by senior tuberculosis laboratory supervisors under training at a reference laboratory in India.

ABSTRACT

Background: A national reference laboratory imparting training on sputum AFB smear microscopy to fresh Senior Tuberculosis Laboratory Supervisors (STLS). Aim: To assess the proficiency of STLSs under training to read sputum AFB smears. Methods: Each of 342 trainees read the same set of 15 to 20 Ziehl Neelsen stained smears in a blinded fashion on day– 1 and on day-15 of the training programme. The smear results were matched with the original results. Observations The sensitivity, specificity, positive predictive value and negative predictive value of smear reading were 75%, 88%, 93%, 63% and 94%, 99%, 99%, 89% respectively on day-1 and day –15. Conclusion: The sensitivity to read sputum AFB smears by fresh STLSs with little or no experience increased from 75% to 94% during the carefully planned training programme; the specificity increased from 88% to 99%. The study highlights the importance of training in improving the microscopy results.