Test Catalog

Test ID: PKUBS    
Phenylalanine and Tyrosine, Blood Spot

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

A 3-mm disk is punched out of the blood spot onto a 96-well plate. The amino acids are extracted by the addition of methanol and known concentrations of isotopically labeled amino acids as internal standards. The extract is moved to another 96-well plate and dried under a stream of nitrogen. Analytes are measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). The concentrations of the phenylalanine and tyrosine are established by computerized comparison of ion intensities of these analytes to that of the respective internal standards.(Unpublished Mayo method)

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.

Monday through Friday; 9 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 Clinic Laboratories until the release of the test result

7 days

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

1 year

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