Final answer:
The disadvantage of Modified Sandwich testing involves a greater potential for false-positive results and less quantitative accuracy than standard tests, which can lead to misinterpretation when used by non-professionals.
Step-by-step explanation:
The disadvantage of Modified Sandwich testing, a term that can refer to modified versions of enzyme-linked immunosorbent assay (ELISA) tests, such as lateral flow tests, includes the potential for false-positive results. This is a concern when these tests are used outside of a professional medical environment, as they may be misinterpreted by individuals without proper medical training. Another limitation is the relative lack of quantification compared to standard ELISA tests, meaning that while they can indicate the presence of a substance, they are less effective at measuring its precise concentration.