Clinical Pathology

 

 May 9, 2014

Siemens has informed the Clinical Laboratory that samples containing fluorescein dye can produce falsely depressed TSH values. With fluorescein intereference TSH can be as low as <0.01 mlU/L.  Evidence suggests that patients undergoing fluorescein dye angiography can retain small amounts of fluorescein for up to 48 to 72 hours post-treatment.  In the cases of patients with renal insufficiency, retention could be much longer.