Test Catalog

Test ID: ACMFS    
Acetylcholine Receptor Modulating Antibody, Flow Cytometry Assay, Serum

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

This method uses flow cytometry to measure the loss of acetylcholine receptors (AChR) expressed on the surface of live cells. The cell line used is an immortalized human rhabdomyosarcoma cell line that expresses endogenous muscle-type nicotinic AChR on its surface. Cells are plated in a 96-well plate and cultured prior to the addition of patient serum, which is then incubated on the cells to enable antibody-mediated internalization of AChR (modulation).


Subsequently, modulation is then stopped and the amount of AChR on the cell surface is measured by flow cytometry. The detection of receptors is performed using a recombinant rat monoclonal antibody specific for the human alpha-subunit of the AChR followed by a secondary goat anti-rat IgG antibody conjugated with allophycocyanin (APC). The amount of AChR on the cell surface is proportional to the median fluorescence intensity (MFI) of APC. To calculate the amount of modulation (ie, % loss of AChR), the APC MFI is compared between cells treated with patient serum and cells treated with serum lacking AChR modulating antibodies. Background signal is established in each experiment utilizing cells stained with secondary antibody alone (no patient sera). The percent loss of AChR is calculated as 1-([Patient MFI-Background MFI]/[Negative calibrator MFI-Background MFI]*100%).(Unpublished Mayo method)

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, Wednesday, Saturday

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.

5 to 8 days

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

28 days

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