The Effect of Sample Handling on Rabies-Neutralizing Antibody Stability

Abstract

The measurement of rabies-neutralizing antibody is important for monitoring the response to rabies vaccination. For all the purposes of measurement, such as routine monitoring of vaccine response in humans and animals, serosurveys, and biologics qualification, accurate and precise results are necessary. The risks associated with sample handling variation, which may impact the test results, can be overlooked within a laboratory. To determine the robustness of rabies-neutralizing antibodies in human and animal serum, samples were treated to mimic various possible deviations in the sample handling protocols. Potential deviations were designed to investigate common client inquiries and possible sample conditions experienced during shipping, storage, and laboratory processes. The treatments included the duration that sera were kept at a temperature greater than that of a refrigerator (room temperature, zero hours to two weeks), the number and duration of heat inactivation treatments (i.e., heat inactivation directly from freezer storage, etc.), the number of freeze–thaw cycles (zero, four, or six cycles), and the storage duration of sample dilutions in chamber slides before the addition of virus (zero hours to overnight). The results provided evidence for the robustness of rabies antibodies and the antibodies’ neutralizing function in uncontaminated, clear human and animal serum. In addition, prolonged heat exposure was identified as exerting the greatest impact on the measurement of rabies antibodies.