Lancet (01/06/96) Vol.347, No.8993, P. 48
The U.S. Food and Drug Administration (FDA) has approved a new
test to detect Mycobacterium tuberculosis in untreated
patients who test positive to a tuberculosis smear test. Gen-
Probe of San Diego, Calif. will manufacture the test, which is
based on "transcription-mediated amplification (TMA)," under
the name Amplified Mycobacterium Tuberculosis Direct Test.
The FDA approved the test based on evidence from 6079 sputum
samples, of which 198 stained positive for acid-fast bacilli.
TMA detects bacterial ribosomal RNA before amplification
begins. RNA is a better target than DNA because it is more
abundant. The test's estimated cost is $15-$25. The FDA has
stated that the test be used only with traditional sputum
examination and culture.