|A COMPARISON BETWEEN LONGITUDINAL AND TRANSVERSE
DIAMETERS OF TUBERCULIN TEST INDURATIONS
|Kul Bhushan, MN Mukherjee, SP Chattopadhya & KT
Ganapathy: Indian J Med Res 1972, 60, 1724-30.
The purpose of this investigation was to compare
the corresponding longitudinal and transverse diameters of tuberculin
test and study the influence of reader variations, size of reaction
and the age specific infection rates, in order to understand the
effect of switching over from the transverse to longitudinal readings.
The study was carried out in villages in south India where no BCG
or tuberculin testing had been undertaken. A total of 1240 persons
were given tuberculin test with 1 TU RT 23 in both longitudinal
and horizontal diameters. The indurations were read after 2-4 days
by two readers independently. The study showed that though the longitudinal
diameters were bigger than the corresponding transverse diameters,
these differences did not influence infection rates calculated at
10 mm or more induration level. In National Tuberculosis Institute
(NTI), Bangalore the practice of reading transverse diameter was
altered to longitudinal diameter in the epidemiological surveys
as it was comparatively easier to read the longitudinal diameter.
Obtaining almost similar infection rates at the 10 mm or more level
of induration in this study, irrespective of readers and diameters
has minimized the effect of the changeover from transverse to longitudinal
diameter reading in the epidemiological surveys at NTI. This would
also not pose any problem in comparing the results of NTI studies
with other research studies by any national or international organisation
where transverse diameters have been measured.
|KEY WORDS: TUBERCULIN TEST, LONGITUDINAL, TRANSVERSE,
TUBERCULIN INDURATION SIZE.