CareDx Lab Services

Clinical Lab Services

AlloMap® Testing is currently performed at the CLIA-certified and CAP-accredited clinical laboratory at CareDx® in Brisbane, CA.

The AlloMap test is based on standard quantitative real-time polymerase chain reaction methodology (qRT-PCR)1 using RNA isolated from peripheral blood mononuclear cells (PBMC). qRT-PCR is a proven methodology for sensitive, specific and reproducible gene expression measurement.

CareDx has optimized and standardized the performance of the AlloMap test processes and implemented extensive quality control procedures to ensure reproducible and reliable testing results. Of the 20 genes measured, 11 are used in the calculation of the AlloMap Test score and 9 are used for standardization and quality control.

Quality control testing

The relative expression of the quality control genes used in AlloMap testing provides data to assess the testing process quality.  The Quality Control checks include assessment of:

    • RNA quantity and quality: There must be a sufficient amount of purified RNA to perform 60 qRT-PCR reactions (20 genes in triplicate). The RNA must also meet the purity requirements, which includes testing for the presence of excess genomic DNA, which can interfere with gene expression measurement.
    • Gene-specific measurement ranges: The measured quantity of each gene product must fall within an established range.
    • Efficiency of the qRT-PCR: The output of the polymerase chain reaction process, expected to double the target material every cycle, must fall within defined limits.
    • Precision: Each of the 20 genes is tested in triplicate. The precision of the 3 replicates must be within an established specification.

 

Additional Laboratory Services: AlloMap Score Variability (AMV)

AlloMap® Score Variability: long-term surveillance for heart transplant patients

Need for personalized surveillance

Despite progress in short- and intermediate-term care and management of transplant patients, there remain challenges in optimizing long-term outcomes2.

Service offering to assess long-term risks

CareDx now provides upon request AlloMap Score Variability (AMV) results for patients under surveillance with AlloMap.  AMV is a service offering from CareDx that aids in estimating the risk of one or more of the following future clinical events in heart transplant patients:

    • Graft dysfunction3
    • Death from any cause
    • Re-transplantation

 

AlloMap_clinical_performance

AMV is available upon request from CareDx.  For more information, please email Customer Care at or get the full AMV brochure.

References

        1. Higuchi H., et al. Simultaneous amplification and detection of specific DNA sequences. Biotechnology (N Y). 10(4):413-7. April 1992.
        2. Starling et al. Multicenter Analysis of Immune Biomarkers and Heart Transplant Outcomes: Results of the Clinical Trials in Organ Transplantation-05 Study. Am J Transplant 2015 Aug 10 [Epub Ahead of print].
        3. Graft dysfunction is defined as a clinically significant hemodynamic compromise (left ventricular ejection fraction ≤40%, use of hemodynamic support such as inotropic medications and/or mechanical assist device, hospitalization for treatment of graft failure or dysfunction).
        4. Deng, et al. Low Variability of Intraindividual Longitudinal Leukocyte Gene Expression Profiling Cardiac Allograft Rejection Scores. Transplantation. 2010; 90(4): 459–461.
        5. Deng, et al. Utility of Gene Expression Profiling Score Variability to Predict Clinical Events in Heart Transplant Recipients. Transplantation. 2014; 97(6): 708–714.
        6. Crespo-Leiro, et al. Performance of gene-expression profiling test score variability to predict future clinical events in heart transplant recipients. BMC Cardiovasc Disord. 2015.