Regulatory agencies (such as UNOS, CAP, ASHI, and CLIA) require that a prospective crossmatch test be performed using a serum sample not less than 14 days old prior to the scheduled transplant. The lymphocyte crossmatch assesses the level of circulating antibodies in the potential recipient that are directed against HLA Class I and/or Class II molecules of the donor.
Interpretive report provided.
*Reference ranges may change over time. Please refer to the original patient report when evaluating results.
Collect specimen in sufficient yellow top (ACD) solution A tubes and in a red top (preferred) or SST tube. Send intact specimen at room temperature. Do not refrigerate or freeze. Testing must be performed within 14 days prior to transplant.
5 mL serum
2 mL serum
The Flow Crossmatch uses indirect immunofluorescence to detect human alloantibodies bound to target lymphocytes. IgG antibodies appear to be most associated with rejection; therefore a fluorophore conjugated with anti-human IgG reagent is used to detect the alloantibody binding. A second and third fluorescent parameter is used to delineate the desired cell population (T or B cell). Interpretation of the Flow Crossmatch is done by comparing the fluorescence intensity of the donor’s cells mixed with the patient's serum to the fluorescence intensity of the same donor when mixed with a known negative control serum. This fluorescent value is then converted mathematically into Median Channel Shift (MCS) or Molecules of Equivalent Soluble Fluorochrome (MESF). The final pre-transplant flow crossmatch is evaluated along with the patient’s current antibody screening results and reviewed for concordance.