Mycobacterial Testing in Hospital Laboratories in Korea: Results of a Survey of 40 University or Tertiary-care Hospitals

Kim, Mi Na; Lee, Sun Hwa; Yang, Sung Eun; Pai, Chik Hyun

Abstract

BACKGROUND
Although tuberculosis has often been referred to as diseases of the past, the current prevalence of active tuberculosis is still about 1% and it is 10th leading cause of death in Korea. In United States where tuberculosis has resurged since 1985, mycobacteriology laboratories have been playing a pivotal role in the control of tuberculosis by providing sensitive and rapid diagnostic tests. In Korea, the extent of mycobacteriology services at hospital laboratories has never been documented, although they too should play a central role in controlling tuberculosis. The purpose of this survey is to assess the facility and testing methods of mycobacteriology laboratories and the turnaround times of diagnostic tests. METHOD: In January 1997, the mycobacteriology laboratory of 40 tertiary or university hospitals in Korea were asked to complete a questionnaire involving mycobacterial test methods, test volume, turnaround time (TAT) for AFB stain. TATs for isolation, identification, and susceptibility testing were collected from the laboratory of Asan Medical Center.
RESULTS
Of the 40 laboratories participating in this survey, AFB mciroscopy was performed at 40, cultures at 38, and susceptibility tests only at two laboratories. 38 laboratories referred susceptibility tests to other non-hospital laboratories. TATs for AFB microscopy were < or =24 hrs at 34 laboratories and 24-36 hrs in 6 laboratories. Isolation/identification and susceptibility tests for mycobacteria took 40.4+/-13.2 days and 45.7+/-12.4 days, respectively. All but one laboratory used solid media, mostly Ogawa media, for primary culture, and for AFB stain, 37 laboratories were using Ziehl-Neelsen method. For identification of AFB, only 4 laboratories were using a nucleic acid probe method, 18 laboratories biochemical tests, and 16 laboratories no identification test except AFB stain.
CONCLUSION
Long TATs were the common and serious problems in mycobacteriology laboratories in Korea. There are urgent needs for optimizing their testing procedures if they were to play a role in the control of tuberculosis in this country. They include introduction of broth media for cultures and susceptibility tests as well as rapid methods for identification.