What is the required state of retention for positive EIA test samples?

The correct answer is that positive EIA (Equine Infectious Anemia) test samples must be frozen for retention. This is important because freezing the samples preserves the integrity of the viral components and antibodies, ensuring that they can be accurately retested or analyzed later if needed. The virus poses significant risks to equine health, so proper preservation is essential for any future investigations, monitoring, or research purposes.

Maintaining the sample at room temperature, on the other hand, could lead to degradation of the sample quality and affect the reliability of test results. Refrigeration is not sufficient for long-term storage either, as the pathogens in the samples may still degrade over time. Vacuum sealing does not address the need to keep samples at a very low temperature, which is critical for the long-term viability of the sample. Thus, freezing is the best method to ensure that positive EIA test samples remain viable for future use.