Cardiac troponins I and T: molecular markers for early diagnosis, prognosis, and accurate triaging of patients with acute myocardial infarction

Acute myocardial infarction (AMI) is the leading cause of death worldwide, with early diagnosis still being difficult. Promising new cardiac biomarkers such as troponins and creatine kinase (CK) isoforms are being studied and integrated into clinical practice for early diagnosis of AMI. The cardiac-specific troponins I and T (cTnI and cTnT) have good sensitivity and specificity as indicators of myocardial necrosis and are superior to CK and its MB isoenzyme (CK-MB) in this regard. Besides being potential biologic markers, cardiac troponins also provide significant prognostic information. The introduction of novel high-sensitivity troponin assays has enabled more sensitive and timely diagnosis or exclusion of acute coronary syndromes. This review summarizes the available information on the potential of troponins and other cardiac markers in early diagnosis and prognosis of AMI, and provides perspectives on future diagnostic approaches to AMI.

Rapid liposomal agglutination card test for the detection of antigens in patients with active tuberculosis

SETTING

A total of 1360 subjects with clinically confirmed pulmonary and extra-pulmonary tuberculosis (TB) and other non-tuberculous conditions.

OBJECTIVES

To develop a rapid, sensitive and specific diagnostic test for the detection of the glycolipid antigen of Mycobacterium tuberculosis in a variety of clinical samples.

STUDY DESIGN

Affinity-purified rabbit anti-glycolipid antibodies (IgG) were coupled to liposome particles (0.2-0.4 microm) in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinamide to prepare the working reagent of the TB/M card test.

RESULTS

Antibody-conjugated liposomes, when determined with the glycolipid antigens present in the specimens, formed a dark blue agglutination within 4 min. No clumping was observed in samples from normal healthy subjects or patients with other diseases. The test was shown to be effective in detecting glycolipid antigens of M. tuberculosis in clinical samples from patients with active TB with as low as 1 ng/ml analytical sensitivity, 97.4% clinical sensitivity and 96.9% specificity.

CONCLUSION

The TB/M card test was found to be comparatively economical (4 Indian Rupees or US$ 0.09/test), rapid (4 min) and seems fairly useful for mass testing of a variety of biological specimens (cerebrospinal, pleural and synovial fluids, serum, tissue biopsy extract) from patients with tuberculous meningitis, pulmonary TB and other extra-pulmonary TB in endemic countries.