Analytical Validation of a Laboratory-Developed Lung Nodule Risk Reclassifier Assay.

BACKGROUND: Lung cancer is the second leading cause of death in the United States. Lung cancer is often diagnosed in its late stage leading to a poor prognosis. Lung nodules are often described as indeterminate from CT scans resulting in lung biopsies that are invasive and may lead to complications. The need for noninvasive methods to assess malignancy risk in lung nodules is great. METHODS: The lung nodule risk reclassifier assay consists of 7 protein biomarkers: Carcinoembryonic Antigen (CEA), C-X-C Motif Chemokine Ligand 10 (CXCL10), Epidermal Growth Factor Receptor (EGFR), Neutrophil Activating Protein-2 (NAP2), Pro-surfactant Protein B (ProSB), Receptor for Advanced Glycation Endproducts (RAGE), and Tissue Inhibitor of Metalloproteinase Inhibitor 1 (TIMP1) and 6 clinical factors (subject age, smoking pack years, and sex, and lung nodule size, location, and spiculated appearance). The protein biomarker assays comprise a multiplex immunoassay panel printed on giant magnetoresistance (GMR) sensor chips as components of a printed circuit board (PCB) run on the MagArray MR-813 instrument system. The analytical validation consisted of imprecision, accuracy, linearity, limits of blank, and limits of detection studies for each biomarker. Several reagents, as well as PCBs, were used in these studies. The entire validation study also assessed multiple users. RESULTS: This laboratory-developed test (LDT), using the MagArray platform, meets the manufacturer's specifications for imprecision, analytical sensitivity, linearity, and recovery. Common biological interferents are known to interfere with the detection of each biomarker. CONCLUSIONS: The lung nodule risk reclassifier assay performed as required to be offered as an LDT in the MagArray CLIA-certified laboratory.

Analytical validation of a novel multi-analyte plasma test for lung nodule characterization.

BACKGROUND: In the National Lung Screening Trial, 96.4% of nodules had benign etiology. To avoid unnecessary actions and exposure to harm, individuals with benign disease must be identified. We describe herein the analytical validation of a multi-analyte immunoassay for characterizing the risk that a lung nodule found on CT is malignant. Those at lower risk may be considered for serial surveillance to avoid unnecessary and potentially harmful procedures. While those nodules characterized at higher risk may be appropriate for more aggressive actions. OBJECTIVE: To validate the analytical performance of multiplexed plasma protein assays used in a novel test for lung nodule characterization. METHODS: A multiplexed immunoassay panel for the measurement of plasma proteins in current smokers who present with a lung nodule on CT scan was evaluated in a clinical testing laboratory. Assay analytical sensitivity, reproducibility, precision, and recovery of Epidermal Growth Factor Receptor (EGFR), Prosurfactant protein B (ProSB), and Tissue Inhibitor of Metalloproteinases 1 (TIMP1) from human EDTA plasma samples were evaluated across multiple runs, lots, and technicians. Interfering substances and sample pre-analytical storage conditions were evaluated for their effect on analyte recovery. The lung nodule risk score reproducibility was assessed across multiple lots. RESULTS: The assay sensitivities were 0.10 ng/mL EGFR, 0.02 ng/mL ProSB, and 0.29 ng/mL TIMP1 with over three orders of magnitude in the assay dynamic ranges. The assays and analytes are robust to pre-analytical sample handling and the plasma can be stored for up to 4 days at 4°C either when freshy collected or thawed after long-term storage at -80°C. Total imprecision after 20 days of testing remained under 9% for all three assays. Risk score variability remained within a ± 10% risk score range. CONCLUSIONS: The three protein assays comprising the multi-analyte plasma test for lung nodule characterization performed quite acceptably in a clinical laboratory.