Refrigeration is not necessary for measurement of uric acid in patients treated with rasburicase

Clin Chem Lab Med. 2013 May;51(5):1053-7. doi: 10.1515/cclm-2012-0300.


Background: 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.

Methods: 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.

Results: 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.

Conclusions: Cold handling (prechilled tubes, iced transportation, 4°C centrifugation) was equivalent to RT for immediate measurement. An additional 1 h delay at RT led to a 20% decrease in uric acid. The cold handling measures required by the manufacturer are not necessary for uric acid testing of patients receiving rasburicase treatment, if testing is performed without delay.

MeSH terms

  • Blood Chemical Analysis
  • Humans
  • Refrigeration*
  • Specimen Handling
  • Tumor Lysis Syndrome / blood
  • Tumor Lysis Syndrome / drug therapy*
  • Urate Oxidase / blood
  • Urate Oxidase / metabolism
  • Urate Oxidase / therapeutic use*
  • Uric Acid / blood*


  • rasburicase
  • Uric Acid
  • Urate Oxidase