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Test ID: TXBU
11-Dehydro-Thromboxane B2, Urine

Method Description Describes how the test is performed and provides a method-specific reference

The method used is liquid chromatography-tandem mass spectrometry (LC-MS/MS). If samples arrive frozen, they are first thawed in a 37 degree C water bath for 15 minutes, vortexed, and returned to the water bath for another 15 minutes to reconstitute all native 11-dehydro-thromboxane B2 (11-dTXB2). Samples are adjusted to a pH of 2.0+/-0.2 and incubated for 3 hours at ambient temperature to force all the urinary thromboxane into the closed ring form that is recognized by the LC-MS/MS method. After addition of d4 internal standard (d4-11-dTXB2) to the sample, 11-dTXB2 is separated from the urine matrix via turbo flow online extraction. A Cyclone MAX anion-exchange column is used for the extraction, while a Waters Xbridge C18 is used for separation from other prostaglandins. From this column, the sample is transferred to an API 5000 MS/MS for instrumental analysis. The specific transitions for mass-to-charge ratio (m/z) 367 to m/z 161 and m/z 371 to m/z 165 for 11-dTXB2 and d4-11-dTXB2, respectively, are monitored. (McConnell JP, Lueke, AJ, et al: Quantitative measurement of 11-dehydrothomboxane B2 in native urine by liquid chromatography tandem mass spectrometry. Clin Chem 2008:54[6]:A98)

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.

Wednesday; 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.

3 days

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

10 days

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 week

Performing Laboratory Location The location of the laboratory that performs the test

Rochester