['Rasburicase, used for hyperuricemia of tumor lysis syndrome, retains activity at room temperature (RT) in in vitro studies. Cold-temperature handling is recommended for uric acid measurements in patients receiving rasburicase: collection in prechilled tubes, transportation on ice, and 4°C centrifugation. We performed a prospective study of these requirements.', 'A total of 65 pairs of blood samples were collected from 34 patients, 12-24 h after receiving rasburicase. The effect of temperature on uric acid concentration was tested on paired samples handled either at RT or when cold: centrifugation (18 sample pairs), collection tube (14 pairs), transportation (24 pairs), and nine pairs were retested after 1 h at RT.', 'No significant temperature effect was seen on the uric acid measurements for any of the cold-handling steps: proportional, absolute biases were -1.4%, -0.06 mg/dL (centrifugation), -1.5%, +0.02 mg/dL (tube temperature), and -2.2%, -0.01 mg/dL (transportation). A 20% negative bias was seen in samples retested after 1 h at RT.'] Is refrigeration necessary for measurement of uric acid in patients treated with rasburicase?