A proof-of-concept point-of-care test for the serodiagnosis of human amebic liver abscess.

BACKGROUND

Amebic liver abscess (ALA), caused by an extraintestinal invasion of the virulent protozoan , is important among parasitic causes of morbidity and mortality, especially in the tropics. Clinical symptoms, medical-imaging abnormalities of the liver and serological tests are normally made for supportive diagnosis. Serum-based enzyme-linked immunosorbent assay (ELISA) has been conventionally used for diagnosing ALA but is time-consuming and sophisticated equipment is required. Therefore, we sought to develop a new and rapid innovative point-of-care immunochromatographic test (ICT) that can use whole blood as an alternative to serum-based ELISA. An ICT tool using simulated whole-blood samples was developed for immunoglobulin G antibody detection, and its diagnostic efficiency was evaluated in comparison with serum-based ELISA.

METHODS

Both methods were tested to assess their diagnostic performance using a total of 253 serum samples. These came from ALA patients ( = 13), healthy individuals ( = 40), and patients with other diseases ( = 200).

RESULTS

Amebiasis-ICT exhibited 100% (95% confidential interval (CI) [75.3-100.0]) sensitivity and 97.1% (95% CI [94.1-98.8]) specificity, whereas ELISA gave the same sensitivity (100% 95% CI [75.3 -100.0]) and slightly lower specificity (95.8% 95% CI [92.5-98.0]). There were no significant differences in sensitivity and specificity between the two tests (Exact McNemar's test; > 0.05), with Cohen's kappa agreement 96.44% (-value = 0.771, < 0.001) indicating substantial agreement.

CONCLUSION

This ICT tool using simulated whole-blood samples has a high possibility of being used with real whole blood. Therefore, since there is no need to separate serum, this can be considered an innovative diagnostic tool to replace serum-based ELISA in clinics and field surveys in remote areas where medical facilities are limited.