A study was done to evaluate inter and intrareader differences in reading of smears stained by Fluorescent Method (FM) and Modified ZN Staining (CS) methods and variation in multiple smears made from the same specimens in order to find out to what extent sensitivity and specificity are influenced by repeated sputum smears from same specimens, by change of readers or by repeated reading.

Eighty sputum specimens with known results, 35 negative and 45 positive with different grades were selected. Ten smears were prepared from each specimen. All the smears were first examined by FM and later by CS method. Culture was also done for these specimens. The findings were: (i) FM was more sensitive than CS method. The specificity appeared to be equal in both. (ii) Change of readers influenced the relative sensitivity of both methods, but repeated examination by the same reader had no effect. (iii) Both reader as well as reading influenced the specificity of FM method but not that of CS method. (iv) Repeated sampling from the same specimen had no effect on the sensitivity of both the methods, while it had some effect on the specificity of FM method. (v) Consistency among readers and readings was found to be poor in smears with low grade positivity. (vi) The relative sensitivity of any method was influenced by the proportion of low grade positive cultures in the total pool. (vii) Examination of multiple smears from the same specimen by more than one reader and more than one reading by the same reader was more rewarding in CS method.

A study was done to compare (1) the filtration method with conventional centrifugation method for the recovery of tubercle bacilli from urine and (2) drug sensitivity profile, virulence for guinea pigs and phage type of the urine isolates with the corresponding isolates from the sputum of cases of bacillary pulmonary tuberculosis.

Urine specimens from 236 pulmonary tuberculosis patients were cultured by routine centrifugation method as well as filtration method. Filtration was done by passing urine through a 0.45 um membrane filter and treating the membrane with 5% oxalic acid for 15 minutes. LJ medium was used for culture in both the methods. Centrifugation yielded 27 positives (11.6%) whereas filtration gave 12 (12.6%) out of 95 specimens filtered. Contamination was more with filtration method. Comparison of the biological properties of M.tuberculosis isolated from urine and sputum of the same patients revealed difference in drug sensitivity profile or virulence for guineapigs for 13 of 25 (52%) of the pairs of isolates tested. Moreover 4 of 11 pairs subjected to phage typing were found to differ in both major and minor phage types. The significance of these findings in the light of the pathogenesis of tuberculosis is also discussed.

The limitation of microscopy, culture and radiology in the diagnosis of tuberculosis, especially smear negative and extra pulmonary, are well known. Hence, attempts have been going on to find a suitable serodiagnostic test. One such test was based on Kaolin Agglutination using tuberculo phosphatide as antigen. A study was done to find out the usefulness of this test in the diagnosis of pulmonary tuberculosis. Serum specimens from 297 newly diagnosed tuberculosis patients and 208 healthy controls, were subjected to Kaolin Agglutination Test (KAT) using tuberculo phosphatide as antigen. Of the 297 X-ray positives, 184 were sputum smear positive and 237 were culture positive for M.tuberculosis. A titre of >= 16 was taken to be diagnostic.

The test picked up 53.6 percent of the culture positives and 54.0 percent of the microscopy positives correctly. Also, 48.8 percent of the X-ray positives and 14.2 percent of the healthy controls were found positive. The overall sensitivity of KAT was 53.6 percent and specificity 85.8 percent which does not make the test suitable for diagnosis of tuberculosis.