Estradiol immunoassays – interference from the drug fulvestrant (Faslodex®) may cause falsely elevated estradiol results

Manufactured by Siemens Healthcare Diagnostics Inc. / Siemens Healthcare Diagnostics Ltd and Roche Diagnostics GmbH- assay interference from the drug fulvestrant (Faslodex®) may cause falsely elevated estradiol results. Both Siemens and Roche have issued field safety notices (FSNs) highlighting this issue. Estradiol assays from other manufacturers may also be affected by fulvestrant (Faslodex®) interference and this is currently under investigation (MDA/2016/004).