An analysis of reference laboratory (send out) testing: an 8-year experience in a large academic medical center

Utilization of outside reference laboratories for selected laboratory testing is common in the United States. However, relatively little data exist in the literature describing the scope and impact of these services. In this study, we reviewed use of reference laboratory testing at the Massachusetts General Hospital, a large urban academic medical center in Boston, Massachusetts.

A retrospective review of hospital and laboratory administrative records over an 8-year period from fiscal years (FY) 1995-2002.

Over the 8 years studied, reference laboratory expenses increased 4.2-fold and totaled 12.4% of the total laboratory budget in FY 2002. Total reference laboratory test volume increased 4-fold to 68,328 tests in FY 2002 but represented only 1.06% of the total test volume in the hospital. The menu of reference laboratory tests comprised 946 tests (65.7% of the hospital test menu) compared to 494 (34.3%) of tests performed in house. The average unit cost of reference laboratory tests was essentially unchanged but was approximately 13 times greater than the average unit cost in the hospital laboratory. Much of the growth in reference laboratory cost can be attributed to the addition of new molecular, genetic, and microbiological assays. Four of the top 10 tests with the highest total cost in 2002 were molecular diagnostic tests that were recently added to the test menu.

Reference laboratory testing comprises a major component of hospital clinical laboratory services. Although send out tests represent a small percentage of the total test volume, these services account for the majority of the hospital laboratory test menu and a disproportionate percentage of laboratory costs.