| Test Name: |
|
HLA Flow Crossmatch
|
|
|
|
|
|
|
| Test Code(s): |
|
XMFLOWS / HCXMFLOWS (if Pre-Tx), XMFLOWB/ HCXMFLOWB (if Post-Tx)
|
|
|
|
|
|
|
| CPT Code(s): |
|
86825 x 2
|
|
|
|
|
|
|
| Test Description: |
|
Test Component: Includes flow cytometry crossmatch for T-cells (CD3+) and B-cells (CD19+) to test for HLA class I and II antibodies against a particular organ donor or potential donor.
|
|
|
|
|
|
|
| Methodology: |
|
Flow Cytometry
|
|
|
|
|
|
|
| Clinical Significance: |
|
Positive flow crossmatch may indicate increased risk of antibody mediated organ rejection.
|
|
|
|
|
|
|
| Days Performed: |
|
Mon-Fri, 0800-1700.
|
|
|
|
|
|
|
| Turnaround Time: |
|
Stat: 4 hours.
Routine: 2 - 3 working days.
|
|
|
|
Specimen Requirements
|
|
|
|
| Specimen: |
|
Blood
|
|
|
|
|
|
|
| Collection Container: |
|
Preferred: Red top
|
|
|
|
|
|
|
| Collection Volume: |
|
Preferred: 4 mL
Pediatrics: 1 mL
|
|
|
|
|
|
|
| Sample Analyzed: |
|
Serum
|
|
|
|
|
|
|
| Volume Required: |
|
Preferred: 2 mL
Pediatrics: 0.5 mL
|
|
|
|
|
|
|
| Specimen Processing: |
|
Note: above sample is for the recipient. Potential donor blood must also be collected and submitted, minimum of 9 mL of blood collected in sodium heparin or ACD anticoagulant. Patient serum and donor cells may be available frozen in the UWHC HLA Laboratory -- call for availability, and indicate if lab should use specimens from storage in the lab.
|
|
|
|
|
|
|
| Specimen Transport: |
|
Transport patient specimen at room temperature or refrigerated to the UWHC HLA Lab, D4/231.
Donor specimen must be collected, transported at room temperature, and received in the laboratory no later than noon on working days and within 2 days of collection.
|
|
|
|
|
|
|
| Stability: |
|
Ambient: Patient serum, 5 days
Refrigerated: Patient serum, 7 days
Frozen: Patient serum, two weeks
|
|
|
|
Interpretation
|
|
|
|
|
|
|
The laboratory will produce a report of the determination of "positive", "negative", or "indeterminate", based on the median channel shift (MCS) from a negative control serum. The MCS value will also be reported, and may be useful for the clinician to assess the risk of transplant despite a result of "positive".
Positive cutoff values, as of 5/1/10:
T-cell (CD3): 80 MCS
B-cell (CD33): 127 MCS
This data must be considered in conjunction with other laboratory results (i.e., Luminex antibody testing) and clinical risk factors prior to transplant.
|
T-cell (CD3) Result
|
B-cell (CD19) Result
|
Clinical Interpretation
|
|
Negative
|
Negative
|
Negative: Compatible
|
|
Positive
|
Positive
|
Positive: Increased risk of rejection
|
|
Negative
|
Positive (strong)
|
Probable Class II antibody
|
|
Positive
|
Negative
|
Not HLA-specific antibody (pattern has been seen with weak Class I antibody)
|
|
Positive (weak)
|
Positive
(weak)
|
Weak antibody, possible non-HLA antibody
|
|
|
|
|
|
|
|
| Test Limitations: |
|
Patients undergoing antibody modulation by means of IvIg therapy and having recent treatment by antibody-based immunosuppressant drugs (Rituximab, Thymoglobulin, Campath, etc) may present with a false positive flow cytometric crossmatch while lacking donor-specific HLA antibodies. Please alert the UWHC HLA Laboratory to any recent (within 2 months) immunosuppressive therapy.
|
|
|
|
|
|
|
| Additional Information: |
|
This test was developed and its performance characteristics determined by this laboratory. It has not been cleared or approved by the US Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. This test is used for clinical purposes. It should not be regarded as investigational or for research. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88) as qualified to perform high complexity clinical laboratory testing.
|
