Test Catalog

Test ID: BTKFP    
Bruton Tyrosine Kinase (BTK) Genotype and Protein Analysis, Full Gene Sequence and Flow Cytometry, Blood

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

Genomic DNA is first extracted from whole blood, followed by BTK gene amplification by PCR. The PCR product is purified from unincorporated primers and nucleotides by enzymatic digestion and sequenced in both directions using sequencing primers and fluorescent dye-terminator chemistry. Sequencing products are separated on an automated sequencer and trace files are analyzed for variations in the exons and intron/exon boundaries of all 19 exons using specialized variant detection software and visual inspection.(Unpublished Mayo method)


The Bruton tyrosine kinase (Btk) protein expression flow cytometry assay is carried out with a whole blood sample. The cells in the blood are stained with antihuman CD20 (B cells) and CD14 (monocytes) antibodies, followed by RBC lysis (using a premade Lysis buffer), cell fixation and permeabilization to prepare the cell membrane for the antihuman Btk antibody. After the permeabilization step, the cells are stained for intracellular Btk using an antihuman Btk-fluorescent preconjugated antibody from BD Biosciences. After the staining and wash process, the cells are resuspended in 500 mcL of BD FACS stain buffer in the final step of the assay and the sample is analyzed by multiparametric flow cytometry.(Unpublished Mayo method; Futatani T, Miyawaki T, Tsukada S, et al: Deficient expression of Bruton's tyrosine kinase in monocytes from X-linked agammaglobulinemia as evaluated by a flow cytometric analysis and its clinical application to carrier detection. Blood 1998;91[2]:595-602)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

4 to 6 weeks

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

Whole Blood: 4 days Extracted DNA: 2 months

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