Carbohydrate Deficient Transferrin for Congenital Disorders of Glycosylation, Serum
Method Description Describes how the test is performed and provides a method-specific reference
Samples are prepared by diluting serum (25 microliters) in water (100 microliters). Ten microliters of the diluted sample is then injected into a 200 microliters/minute flow of pH 7.4 phosphate buffer saline (PBS) and retained on an immunoaffinity column that is composed of 60% antihuman apolipoprotein CIII antibody and 40% antihuman transferrin antibody bound to POROS 20 AL media. The immunoaffinity column is then washed for 2 minutes with PBS. Following the 2-minute wash, captured proteins are eluted to a C4 column at 200 microliters/minute with pH 2.5 100mM glycine/2% acetic acid buffer for 2.5 minutes. The C4 column is then washed for 1 minute with water/methanol/glacial acetic acid (97/2/1) at 200 microliters/minute to remove signal-suppressing salts. The proteins are then eluted from the C4 column with methanol/water/glacial acetic acid/TFA (94.5/5/0.5/0.04) at 200 microliters/minute and introduced into an API 4000 tandem mass spectrometer equipped with a Turbo V source configured for electrospray ionization. The mass spectrometer is operated in positive Q1 scan mode with 2 scan ranges; m/z 1090-2000 for apolipoprotein CIII and m/z 2000-3000 for transferrin. The total analysis time is 8 minutes, including column equilibration. Relative quantitation of carbohydrate deficient transferrin and apolipoprotein CIII is achieved by comparing glycoform ratios in each protein.(Lacey JM, Bergen R, Magera MJ, et al: Rapid determination of transferrin isoforms by immunoaffinity liquid chromatography and electrospray mass spectrometry. Clin Chem 2001;47:513-518)
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,Thursday; 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.
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