Hemagglutination tests for tuberculosis with mycobacterial glycolipid antigens. Results in patients with active pulmonary tuberculosis before and during chemotherapy and in healthy tuberculosis contacts.

Hemagglutination tests using three serologically active mycobacterial glycolipids as antigens were carried out on serum specimens from patients with pulmonary tuberculosis and from healthy family contacts of patients with tuberculosis in Singapore. A positive response to any of the three antigens was found in 82.5% of 211 patients with newly diagnosed disease and in 21% of 100 contacts. The much higher proportion of positive results in the contacts than in other groups of healthy subjects previously reported might have been due to subclinical infection with tubercle bacilli or with other environmental mycobacteria. The use of rules derived from discriminant analysis improved discrimination between patients and contacts, so that a positive result was obtained in 72% of patients and 5% of contacts. Serial positive titers during 1 yr of chemotherapy showed an initial slight increase during the first month and then a slow decrease, although conversion from a serologically positive result to a negative result was uncommon. The occurrence of widely variable patterns of response to the three antigens in different patients emphasizes the importance of using a battery of tests, each with a separate antigen.