Xanthine and Hypoxanthine, 24 Hour, Urine
Method Description Describes how the test is performed and provides a method-specific reference
Diluted, filtered urine is mixed with an internal standard (8-13 C Adenine) and analyzed for xanthine and hypoxanthine by liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS is performed using a mobile phase composed of 50-mM ammonium formate, ph=5, and 1:1 mixture of 50-mM ammonium formate, ph=5: methanol and run using a gradient. An Xterra MS C18 column (2.1 x 150 mm) is used to separate xanthine and hypoxanthine from the bulk of the specimen matrix. The MS/MS is operated in the selected reaction monitoring (SRM) scanning mode. The ratios of the extracted peak areas of xanthine and hypoxanthine to an internal standard are used to calculate the concentration of xanthine and hypoxanthine present.(Ito T, van Kuilenburg AP, Bootsma AH, et al: Rapid screening of high-risk patients for disorders of purine and pyrimidine metabolism using HPLC-electrospray tandem mass spectrometry of liquid urine or urine-soaked filter paper strips. Clin Chem 2000;46:445-452)
PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Varies; Batched 1 time per week; 8 a.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
7 days (Not reported Saturday or Sunday)
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test