An immunochromatographic test for the diagnosis of ricin inhalational poisoning.

Introduction: Aerosolized ricin is a feared bioweapon for which no diagnostic protocol is currently available.

Methods: We obtained antibodies to develop an immunochromatographic test (ICT) that would be part of such a protocol.

Results: Our ICT, that can be read with the naked eye, has a sensitivity of 1 ng ricin/mL buffer, without enhancement, making it the most sensitive rapid test available for this toxin as far as we know. Its dynamic range extends to 10 microg/mL, with a plateau from 10 to at least 250 microg/mL (no "hook effect"), and it has limited cross-reactivity with other lectins.

Discussion: Calculated from experimental and animal data, sampling with nasal swabs and testing with the devised ICT should give more than a thousand times the sensitivity required to diagnose ricin inhalational poisoning. Such a margin is particularly valuable in the absence of clinical data.

Conclusion: This cost-effective and easy to use diagnostic tool could assist in the diagnosis of inhalational exposure from ricin aerosols.