Linkage of Laboratory Results to Medicare Fee-for-Service Claims

Medicare is the single largest purchaser of laboratory testing in the United States, yet test results associated with Medicare laboratory claims have historically not been available.

The purpose of this study was to describe both the linkage of laboratory results data to Medicare claims and the completeness of these results data. In a subgroup of beneficiaries initiating angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, we also demonstrate the generalizability of Medicare beneficiaries with laboratory values compared with those without laboratory values. We end with a discussion of the limitations and potential uses of these linked data.

We obtained information about laboratory orders and results for all Medicare fee-for-service beneficiaries in 10 eastern states who had outpatient laboratory tests conducted by a large national laboratory services vendor in 2011. Using a combination of direct identifiers and patient demographic characteristics, we linked patients in these laboratory data to Medicare beneficiaries, enabling us to associate test results with existing claims.

Nearly all patients in the laboratory data were able to be linked to Medicare beneficiaries. There were over 2 million distinct beneficiaries with nearly 125 million specific test results in the laboratory data. For specific tests ordered in an outpatient or office setting in these 10 states, between 5% and 15% of them had linked laboratory data. Medicare beneficiaries initiating angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers who had laboratory results data had similar patient characteristics to those without results data.

This novel linkage of laboratory results data to Medicare claims creates unprecedented opportunities for conducting comparative effectiveness research related to patient safety and quality.