Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods that allow accurate quantitation of thyroglobulin (Tg) in the presence of Tg antibodies (TgAbs) have recently become available. Due to cost differences between LC-MS/MS and immunoassay, some laboratories now offer a reflex test strategy that uses LC-MS/MS only for TgAb-positive samples. The goal of this study was to examine utilization of Tg testing strategies and cost savings.
Test ordering patterns were examined for over 150,000 orders for TgAb and Tg in our laboratory. The average list price was determined from three separate commercial laboratories offering this testing.
Data showed that 89% of orders for Tg used the reflex test option, resulting in a savings of over $3 million compared with testing all samples by LC-MS/MS. Of the Tg by LC-MS/MS orders not using the reflex option, 1,663 also included a separate order for TgAb on the same patient sample, representing approximately $170,000 in potentially unnecessary costs from TgAb-negative samples.
Identifying situations to use more expensive testing methods (eg, LC-MS/MS) only when necessary, such as for TgAb-positive patients, leads to considerable cost savings and a more economical use of valuable health care resources.