HEARTBiT Blood-Based Gene Profiling Assay Validated for Heart Transplant Rejection Monitoring
Analytical validation of the HEARTBiT 12-gene NanoString-based blood assay for exclusionary diagnosis of acute cellular rejection in heart transplant patients demonstrated linear performance across 125-500 ng RNA input, less than 3% quantitative bias, approximately 5% CV, and total variation below 0.02 SD units. The assay achieved an AUC of 0.75, offering a non-invasive alternative to endomyocardial biopsy for transplant surveillance in the first post-transplant year.
The original study
Analytical Validation of HEARTBiT: A Blood-Based Multiplex Gene Expression Profiling Assay for Exclusionary Diagnosis of Acute Cellular Rejection in Heart Transplant Patients.
- Authors
- Kim JV, Lee B, Koitsopoulos P, Shannon CP, Chen V, Hollander Z, et al.
- Journal
- Clinical chemistry
- Type
- Journal Article, Research Support, Non-U.S. Gov't, Validation Study
- PMID
- 32705124
Original abstract
BACKGROUND: HEARTBiT is a whole blood-based gene profiling assay using the nucleic acid counting NanoString technology for the exclusionary diagnosis of acute cellular rejection in heart transplant patients. The HEARTBiT score measures the risk of acute cellular rejection in the first year following heart transplant, distinguishing patients with stable grafts from those at risk for acute cellular rejection. Here, we provide the analytical performance characteristics of the HEARTBiT assay and the results on pilot clinical validation. METHODS: We used purified RNA collected from PAXgene blood samples to evaluate the characteristics of a 12-gene panel HEARTBiT assay, for its linearity range, quantitative bias, precision, and reproducibility. These parameters were estimated either from serial dilutions of individual samples or from repeated runs on pooled samples. RESULTS: We found that all 12 genes showed linear behavior within the recommended assay input range of 125 ng to 500 ng of purified RNA, with most genes showing 3% or lower quantitative bias and around 5% coefficient of variation. Total variation resulting from unique operators, reagent lots, and runs was less than 0.02 units standard deviation (SD). The performance of the analytically validated assay (AUC = 0.75) was equivalent to what we observed in the signature development dataset. CONCLUSION: The analytical performance of the assay within the specification input range demonstrated reliable quantification of the HEARTBiT score within 0.02 SD units, measured on a 0 to 1 unit scale. This assay may therefore be of high utility in clinical validation of HEARTBiT in future biomarker observational trials.