He indicated that by the end of April there may be a nationwide sample with results starting to build. Policy decisions could be made on that data by the middle of May, which would be a huge step in the right direction.

Think about it this way. If the disease is dramatically more widespread than our "confirmed cases" suggest (meaning 20x to 100x more widespread) then we've already hit between 10-50% saturation and by the middle of May this will likely already be blowing over. That said, if these anti-body tests aren't performed then we still won't know whether or not that's the case. We'd see a huge drop in hospitalizations and deaths at that time, but everyone would be debating whether: (i) the measures for flattening the curve dropped it with a future ticking time bomb where things will ramp up again once removed (hence they need to stay in place), or (ii) the population is actually reaching the saturation point and we're hitting the back end of the curve.

If it's truly hitting the back end of the curve and scenario then a lot of decision makers and "scientists" who have been advising governmental leaders will have a ton of egg on their faces and there will be tremendous resistance to admitting that mortality and hospitalization projections were off by an order of magnitude and the measures likely had little or no effect because of how widespread the disease already was. We need data and this is the most important piece for us to stop flying blind.