The enigma surrounding coffee-colored serum

Abnormal discoloration of body fluids like serum or urine has been reported in the literature as a pharmacological adverse effect. Herein we report a patient with coffee-colored serum as an adverse effect of eltrombopag. Therefore, we alert the laboratory professionals and highlight the importance of visual inspection of the serum sample in a clinical laboratory and explore the possibilities. Furthermore, eltrombopag at high dose (200mg) can interfere with bilirubin assay based on the methodology used in the detection systems.