This full text paper,
from The American Journal of Managed Care, describes a method to
measure and optimize the impact diagnostic service hours has on length
of stay.

We illustrate how a hospital can profile timeliness, demand, and
capacity utilization across the week for multiple testing areas. This
simple, practical method, using data extracted from the hospital's
accounting system, makes visible the pattern and magnitude of
delays caused by reduced availability on weekends, while also
showing how capacity is deployed.