US HOSPITAL MYCOBACTERIOLOGY LABORATORIES - STATUS AND COMPARISON WITH STATE PUBLIC-HEALTH DEPARTMENT LABORATORIES

In response to the resurgence of tuberculosis, the Centers for Disease Control and Prevention recommended the use of certain mycobacteriolog y laboratory methods to improve the accuracy of diagnosis and/or minim ize times to complete specimen processing, A study to determine the ex tent to which these recommended methods were being used in hospital la boratories was needed, In 1992, a survey was mailed to infection contr ol and laboratory personnel at 1,076 hospitals with greater than or eq ual to 100 beds to determine the mycobacterial laboratory services bei ng performed, the methods being used, the number of specimens being pr ocessed, and the times to completion during 1991, In 1995, a 20% sampl e of hospital laboratories that responded to the initial questionnaire was resurveyed, Responses to the 1992 survey were received from perso nnel at 756 (70%) hospitals representing 750 laboratories. Among labor atories performing the services, the use of recommended methods was as follows: fluorochrome stain for acid-fast bacillus microscopy (47%); radiometric methods for primary culture (29%); rapid (radiometric meth ods, use of nucleic acid probes, high-performance liquid chromatograph y, or gas-liquid chromatography) methods for identification of Mycobac terium tuberculosis (59%); and radiometric methods for drug susceptibi lity testing (55%), Reported times to complete specimen processing wer e shortest for laboratories that used recommended methods and longest for hospitals that referred specimens to outside laboratories. Only 46 % of surveyed laboratories performed at least the minimal number of my cobacterial cultures (20/week) deemed necessary to maintain competence , Among 145 laboratories that performed the services and were resurvey ed in 1995, use of recommended techniques increased from 44 to 73% for acid-fast bacillus microscopy, from 27 to 37% for primary culture, fr om 59 to 88% for M. tuberculosis identification, and from 55 to 75% fo r drug susceptibility testing. These changes were associated with redu ctions in reported specimen turnaround times. Use of the methods recom mended by the Centers for Disease Control and Prevention increased at the resurveyed hospital mycobacteriology laboratories between 1991 and 1995, However, continued efforts are needed to increase the use of re commended methods at moderate- and high-volume laboratories, encourage referral of specimens from low-volume laboratories, and transmit resu lts rapidly from all laboratories.