Flow Cytometry(FC-XM) Crossmatch(T and B cells)

CMDL > Flow Cytometry(FC-XM) Crossmatch(T and B cells)

Intended Use

The flow cytometric lymphocyte cross match is a standard technique for evaluating the compatibility of potential kidney transplant recipient and donor. Recipient serum is incubated with donor lymphocytes and later analysed in a flow cytometer for the presence of bound IgG antibodies.
Specimen Required
  • Recipient:  1 / Red / Plain / 4 mL
  • Donor: 1 / Yellow / ACD-A / 9 mL
Patient Preparation
  • Sample collection:

      Recipient: Fasting Blood Samples preferred

      Donor: Random Blood Samples

  • Specimen preparation: DO NOT FREEZE blood or tissue samples intended for HLA testing or crossmatching, as freezing damages the cells.
  • Storage/Transport Temperature: Samples may be stored temporarily at refrigerated temperatures (4°C to 8°C) prior to dispatch. Ensure they are packaged to maintain this temperature during transit if required by local protocols.
  • Unacceptable Conditions

       Sample older than 24 hours after collection is not suitable

       Lipemic samples will interfere with the reading of results

      Improper mixing of the ACD-A blood (donor blood) will lead to clotting.

      Sample collected within 24 hours of dialysis will not be accepted.

      Haemolysed Samples

  • Remarks :
  • Stability :
Methodology

The Flow Cytometry Crossmatch (FCXM) assay is performed to detect the presence of patient antibodies reactive with donor T and B lymphocytes. Donor lymphocytes (separated total lymphocytes subsequently gated) are incubated with patient serum. Bound IgG antibodies are detected using a FITC-conjugated anti-human IgG antibody.

Analysis is performed on flow cytometer Beckman Coulter Navios. The positive threshold for this assay is determined based on the Median Fluorescence Intensity (MFI) ratio and/or the Mean Channel Shift (MCS) of the patient serum reaction compared to a negative control serum reaction against multiple sets of donor cells. The laboratory has established and validated specific cut-off values for MFI ratio and MCS to define a positive crossmatch.

Sample received to report Turnaround time (TAT)

1 Working Days

Reference Interval

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Interpretive Data

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Interpretive Data

Laboratory Established Cut-offs for Positive Result:

  • T-Cell FCXM: MCS Shift > 63
  • B-Cell FCXM: MCS Shift > 112

Resources

Sample Reports

  • Enhanced Report
  • See report