I think part of it is regression to the mean. Costs have been under pressure for a few years so hospitals are eliminating the gap between their efficiency and the reference lab efficiency. Hospitals also are consolidating which means they are becoming more efficient. Lots of hospital systems are moving towards a central, main lab which is similar to a hub and spoke model. They can run the cheaper, high volume tests at smaller offsites and have much better TAT than the national labs, and move the rarer tests to the central lab and have a similar TAT and probably lesser expense than the national labs. But no doubt physician practices being purchased by hospitals also is relevant here.
